Problem Topics
Difference between en1 and en2, changed 11,651 character(s)
Good Day to you!↵

I've been asked to make some topic-wise list of problems I've solved. Even though I couldn't involve all problems, I've tried to involve at least "few" problems at each topic I thought up (I'm sorry if I forgot about something "easy"). I've alredy made such list once anyway I've tried to include more problems now &mdash; so here it is:↵

<spoiler summary="aho">↵

http://www.spoj.com/problems/SUB_PROB/en/↵

http://codeforces.com/contest/696/problem/D 8↵

http://www.spoj.com/problems/AHOCUR/ 5 //Aho-Corassic + DP↵

https://www.codechef.com/problems/LYRC (5) //Sample aho-brute-force↵

</spoiler>↵

<spoiler summary="automat">↵

6861 [LA] //CYK↵

UVA 10679 //Suffix Automat↵

http://www.spoj.com/problems/STRMATCH/ //Suffix Automat  &mdash; trie might do too↵

http://www.spoj.com/problems/NSUBSTR2/ //Suffix Automaton↵

</spoiler>↵

<spoiler summary="belman-ford">↵

UVA 12519↵

http://www.spoj.com/problems/ARBITRAG/ (4) //Or Floyd-Warshall↵

</spoiler>↵

<spoiler summary="bfs">↵

https://devskill.com/CodingProblems/ViewProblem/60↵

https://devskill.com/CodingProblems/ViewProblem/150↵

11312 UVA (3)↵

11392 UVA (4)↵

http://codeforces.com/contest/653/problem/E (6)↵

http://codeforces.com/contest/769/problem/C 5 //FL:ODD/**** | bfs+greed NICE↵

10968 UVA (3) //EASY + NICE (bfs withot <=2 nodes)↵

http://codeforces.com/contest/796/problem/D (3) //NICE+EASY ... print visited in bfs (not par)↵

10888 UVA (4) //VERY NICE &mdash; but not main technique ... ++ DP /or/ MCMF↵

http://codeforces.com/contest/821/problem/D (5) //VERY NICE &mdash; Consider only points not GRID↵

http://www.spoj.com/problems/DIGOKEYS/ (4) //Easy [Nice problem &mdash; weird statement]↵

http://www.spoj.com/problems/SPIKES/ (3) //Easy bfs (# of 's' * 2)↵

http://www.spoj.com/problems/MULTII/ (4) //VERY NICE: BFS over numbers (K*10+d)%N↵

http://www.spoj.com/problems/ADV04F1/ (5) //VERY NICE: [imple] ~ N^4*BigConstant↵

http://www.spoj.com/problems/INVESORT/ (5) //Big limit (really usefull :P)↵

http://codeforces.com/contest/59/problem/E (5) //[NICE][DOUBLE-STATES][SET]↵

http://codeforces.com/contest/877/problem/D (4) //[NICE] Add vector to # of states↵

</spoiler>↵

<spoiler summary="bfs-grid">↵

10977 UVA (3)↵

928 UVA (3)↵

13116 UVA (4)↵

314 UVA (3)↵

11487 UVA (4)↵

5622 LA (7)↵

11931 UVA (5)↵

http://www.spoj.com/problems/KNMOVE/ 3 //simple knights↵

http://www.spoj.com/problems/SERGRID/ 3 //almost classical↵

http://www.spoj.com/problems/NAKANJ/ 3 //Classical chess &mdash; KNIGHT↵

http://www.spoj.com/problems/PUCMM223/ (4) //NICE (but not many languages) &mdash; 2 moving [x][y]↵

http://www.spoj.com/problems/SPIRALGR/ (4) //NICE (not typical) [SIEVE]↵

http://www.spoj.com/problems/DCEPC706/ (4) //NICE &mdash; travelling outside↵

http://codeforces.com/contest/35/problem/C (3) //No obstacles [multiple starts]↵

</spoiler>↵

<spoiler summary="big">↵

http://codeforces.com/contest/66/problem/A (2) //Big + iffs + implementation↵

UVA &mdash; 10183 ↵

10106 &mdash; Product [UVA]↵

10523 &mdash; Very Easy !!! [UVA]↵

787 &mdash; Maximum Sub-sequence Product [UVA]↵

2871 &mdash; Rhyme Schemes [LA][BELL]↵

UVA &mdash; 10497↵

http://www.spoj.com/problems/MUL/en/↵

http://www.spoj.com/problems/ITRIX_E/↵

11115 &mdash; Uncle Jack↵

11448 &mdash; Who said crisis? [UVA]↵

http://www.spoj.com/problems/GCD2/↵

10083 &mdash; Division [UVA]↵

11830 &mdash; Contract Revision [UVA]↵

1230 &mdash; MODEX [UVA]↵

http://www.spoj.com/problems/NUMPLAY/↵

10519 &mdash; UVA↵

7651 &mdash; Pascal's Hyper-Pyramids [LA]↵

11344 &mdash; The Huge One [UVA]↵

10303 &mdash; How Many Trees? [UVA]↵

http://www.spoj.com/problems/FAST2/↵

495 &mdash; Fibonacci Freeze [UVA]↵

10023 &mdash; Square root [UVA]↵

http://www.spoj.com/problems/SKYLINE/↵

http://www.spoj.com/problems/NITT2/↵

11879 &mdash; Multiple of 17↵

http://www.spoj.com/problems/MINNUM/↵

10494 &mdash; If We Were a Child Again [UVA]↵

10013 &mdash; Super long sums [UVA]↵

10925 &mdash; Krakovia [UVA]↵

10814 &mdash; Simplifying Fractions [UVA]↵

619 &mdash; Numerically Speaking [UVA]↵

713 &mdash; Adding Reversed Numbers [UVA]↵

1226 &mdash; Numerical surprises [UVA]↵

623 &mdash; 500! [UVA]↵

http://codeforces.com/problemset/problem/18/D↵

http://www.spoj.com/problems/NUMTSN/↵

https://www.codechef.com/problems/FRJUMP↵

10220 &mdash; I Love Big Numbers ! [UVA]↵

https://www.hackerrank.com/contests/projecteuler/challenges/euler025↵

https://www.hackerrank.com/contests/projecteuler/challenges/euler020↵

11645 UVA 4↵

Gym &mdash; 100866A [ACM ICPC 2005–2006 NEERC Moscow Subregional Contest]↵

CSQUARE [SPOJ]↵

http://www.spoj.com/problems/PARCARD1/↵

10070 &mdash; Leap Year or Not Leap Year and .. [UVA]↵

http://www.spoj.com/problems/SOLDIERS/↵

12333 &mdash; Revenge of Fibonacci [UVA]↵

http://www.spoj.com/problems/NDIVPHI/↵

http://www.spoj.com/problems/IWGBS/ [UVA]↵

http://www.spoj.com/problems/POP3/ [Prime-Test]↵

http://www.spoj.com/problems/VGCD/↵

http://www.spoj.com/problems/NDIVPHI2/↵

12924 &mdash; Immortal Rabbits [UVA]↵

Count the Trees  [UVA][10007]↵

10198 &mdash; Counting [UVA]↵

11375 UVA 3↵

http://www.spoj.com/problems/MINNUM/ 3 // BIG/9+!!(BIG%9)↵

10844 UVA 4 //Bell numbers + big (might be slightly slow!)↵

http://www.spoj.com/problems/NITT2/ 2 //Divisibility by two constants↵

http://www.spoj.com/problems/NUMPLAY/ (3) //With DP↵

http://www.spoj.com/problems/IWGBS/ (3) //Fibonacci 10^4↵

http://www.spoj.com/problems/PUCMM025/ (2) //Divisibility by 1 → 9↵

http://www.spoj.com/problems/CSQUARE/ (3) //Converse + Power ↵

http://codeforces.com/contest/17/problem/D (5) //B^(N-1)*(B-1)%C [B/N are big]↵

</spoiler>↵

<spoiler summary="binary_search">↵

http://codeforces.com/contest/68/problem/B (3) //[EASY][DOUBLE]↵

http://codeforces.com/contest/42/problem/A (2) //Or simple math↵

http://codeforces.com/contest/883/problem/I (4) //[NICE][SET][2Pointers]↵

http://codeforces.com/contest/51/problem/C (4) //[NICE][GREEDY-CHECK]↵

http://codeforces.com/contest/729/problem/C 3↵

http://codeforces.com/contest/714/problem/D 8↵

13150 (UVA) 4↵

http://codeforces.com/contest/749/problem/D 5↵

11692 (UVA) 4↵

11516 (UVA) 3↵

http://codeforces.com/contest/760/problem/B 3↵

http://codeforces.com/contest/675/problem/D 4 //dunno &mdash; solvable with treap↵

http://www.spoj.com/problems/NDS/ 4 //BS over LIS↵

http://www.spoj.com/problems/VECTAR4/ 3↵

http://codeforces.com/contest/767/problem/D 4 //NICE↵

http://codeforces.com/contest/627/problem/D (7) //with dp &mdash; NICE↵

http://codeforces.com/contest/779/problem/D (3) //NICE + EASY↵

http://www.spoj.com/problems/CNTINDX/ (4) //Map+BS === OK↵

13177 UVA (3) //BS over answer == OK↵

http://codeforces.com/contest/801/problem/C (3) //BS + SUM -EASY↵

http://codeforces.com/contest/807/problem/C (3) //Or math↵

http://codeforces.com/contest/818/problem/F (4) //NICE &mdash; Live VS Clique↵

http://codeforces.com/contest/845/problem/E (5) //VERY NICE &mdash; min(X,Y) .. add time, repeat↵

http://www.spoj.com/problems/MATHLOVE/ (2) //BS + Gaus (or otter ways)↵

http://www.spoj.com/problems/SABBIRGAME/ (3) //Binary search over answer ::max(0,ANS)↵

http://codeforces.com/contest/846/problem/D (4) //BS+Precalculation OR 2D-RMQ↵

http://www.spoj.com/problems/RPLC/ (3) //Classical↵

http://www.spoj.com/problems/TRIGALGE/ (2) //On doubles &mdash; simple function given↵

http://www.spoj.com/problems/ABA12E/ (4) //VERY NICE &mdash; BS on answer + 2Pointers↵

http://codeforces.com/contest/847/problem/E (4) //NICE: Back+Front OR Front+Back↵

http://www.spoj.com/problems/MAIN8_C/ (3) //Classical &mdash; simultion over array↵

http://www.spoj.com/problems/FUNFACT/ (4) //VERY NICE &mdash; Sterling Approximation↵

http://codeforces.com/contest/16/problem/C (3) //[or math][simple formula check]↵

http://codeforces.com/contest/21/problem/C (3) //[NICE][prefix-sum+lower_bound]↵

http://codeforces.com/contest/24/problem/E (5) //[doubles]↵

http://codeforces.com/contest/875/problem/E (6) //VERY NICE [BS][Keep possible places]↵

</spoiler>↵

<spoiler summary="bits">↵

http://codeforces.com/contest/879/problem/C (3) //[NICE] one of each operation is enough↵

http://codeforces.com/contest/92/problem/B (2) //Bit addition/shifting (but big number)↵

11659 UVA (4)↵

11535 UVA (4)↵

http://codeforces.com/contest/779/problem/E (5) //NICE + Parsing↵

http://www.spoj.com/problems/EC_CONB/ (1) //reverse numbers↵

http://codeforces.com/contest/769/problem/D (4) //freq + brute-force↵

http://www.spoj.com/problems/HAP01/ (2) //builtin_popcount↵

http://codeforces.com/contest/862/problem/C (3) //VERY NICE &mdash; Random works well↵

http://www.spoj.com/problems/KOMPICI/ (4) //NICE &mdash; Bitmask over digits↵

</spoiler>↵

<spoiler summary="bitset">↵

http://codeforces.com/contest/754/problem/E 6↵

http://www.spoj.com/problems/UCBINTC/ 5 //polymul with bitset↵

http://codeforces.com/contest/33/problem/D (4) //VERY NICE [LCA works too]↵

</spoiler>↵

<spoiler summary="bridges">↵

315 &mdash; Network↵

UVA 12363↵

Gym 100114J [2012-2013 ACM-ICPC, NEERC, Central Subregional Contest]↵

http://www.spoj.com/problems/ONBRIDGE/ [ONLINE][HARD][NICE][D&C]↵

http://codeforces.com/contest/732/problem/F 7↵

http://codeforces.com/contest/700/problem/C 7↵

http://www.spoj.com/problems/EC_P/ (3) //bridges ONLY↵

http://www.spoj.com/problems/SUBMERGE/ (3) //Direct articulation↵

http://www.spoj.com/problems/GRAFFDEF/ (5) //Bridge tree↵

</spoiler>↵

<spoiler summary="brute-force">↵

http://codeforces.com/contest/94/problem/B (1) //3cycles↵

http://codeforces.com/contest/887/problem/B (3) //Test all numbers↵

http://codeforces.com/gym/101597/problem/A (4) //[MATH][MODULO][SIMULATION]↵

http://codeforces.com/contest/68/problem/C (5) //[VERY NICE][RECURSION][MAX COST MIN FLOW]↵

http://codeforces.com/contest/68/problem/A (1) //Simple simulation↵

http://codeforces.com/contest/66/problem/B (2) //Test always whole platform↵

http://codeforces.com/contest/879/problem/C (3) //[NICE] one of each operation is enough↵

http://codeforces.com/contest/46/problem/C (2) //[2pointers][N^2 works too]↵

http://codeforces.com/contest/47/problem/D (4) //[Implementation][DFS]↵

http://codeforces.com/contest/51/problem/D (4) //Check all/check without 1s/2nd↵

http://codeforces.com/contest/53/problem/B (3) //at most 60 possibilities↵

http://codeforces.com/contest/55/problem/B (3) //Try all permutations & possibilities [NICE]↵

http://codeforces.com/contest/877/problem/B (3) //NICE [N^2][PrefixSum]↵

LA 6623 &mdash; Battle for Silver (3) //4 for-cycles inside ~ K4 search↵

UVA 12169 (2)↵

http://codeforces.com/contest/725/problem/C 4↵

http://codeforces.com/contest/725/problem/E 6↵

http://codeforces.com/contest/724/problem/B 3↵

11961 UVA (2)↵

11898 UVA (4)↵

11659 UVA (4)↵

http://codeforces.com/contest/753/problem/C 7↵

11699 UVA (4)↵

11548 UVA (3)↵

11471 UVA (5) //With dynamic programming↵

http://codeforces.com/contest/698/problem/D 8 //with geometry↵

11206 UVA (6) //4^20 (but somehow passes)↵

11214 UVA (6) //Úvaha + pruning↵

11127 UVA (4) //Simple dfs [just realize you can do so]↵

http://www.spoj.com/problems/BOKAM143SOU/ (3) //just implement for-cycles↵

http://www.spoj.com/problems/BLOPER/ (4) dfs with little pruning↵

13173 UVA (3) //just brute-force + branching↵

http://codeforces.com/contest/799/problem/D (4) //VERY NICE [only top 34 needed] &mdash; trick with 2 [~20]↵

10890 UVA (4) //Simple brute-force times out, but with simple pruning AC (answer detection↵

http://codeforces.com/contest/813/problem/B (3) //All*All (BF) care for overflow! NICE & EASY↵

http://codeforces.com/contest/817/problem/C (3) //Check S+Constant (NICE!)↵

10732 UVA (2) //Brute-force passes .. just don't trust them O(N^2)↵

10748 UVA (5) //VERY Nice (knights have K^2 moves not 8^K)↵

http://codeforces.com/contest/818/problem/D (4) //NICE for each 'A' check all remaining (max SQRT)↵

http://codeforces.com/contest/834/problem/E (5) //NICE &mdash; hard to imple: all 11122...999 OK↵

http://www.spoj.com/problems/JHAGIRLS/ (4) //Efficient &mdash; or store output in array↵

http://codeforces.com/contest/846/problem/B (3) //Brute-force↵

http://www.spoj.com/problems/ALONE/ (4) //Generate everything <10^15 [NICE]↵

http://codeforces.com/contest/861/problem/B (3) //Check all floor-sizes↵

http://www.spoj.com/problems/RRANGE/ (3) //Compare all queries agains all updates + GAUSS↵

http://codeforces.com/contest/598/problem/B (3) //Treap works too ;-)↵

http://www.spoj.com/problems/AMR10I/ (4) //Can be solved with brute-force with dp↵

http://codeforces.com/contest/868/problem/C (4) //Brute-force (fixet at most 6 each bits)↵

http://codeforces.com/contest/868/problem/D (5) //NICE: Maximal K is low (I assumed 15)↵

http://codeforces.com/contest/31/problem/C (2) //LOW-Constaints: N^2↵

http://codeforces.com/contest/32/problem/D (3) //Simply try all possibilities↵

http://codeforces.com/contest/876/problem/C (3) //Try N and ~100 lower↵

http://codeforces.com/contest/44/problem/B (2) //N^2 works fine↵

</spoiler>↵

<spoiler summary="centroid">↵

DCP-176: Motku2 [DevSkills] ↵

http://codeforces.com/contest/715/problem/C 9↵

http://codeforces.com/contest/741/problem/D 8↵

13164 UVA (7)↵

http://codeforces.com/contest/752/problem/F 5↵

http://codeforces.com/contest/766/problem/E 6↵

http://codeforces.com/contest/833/problem/D 7 //Very nice &mdash; hard (thinking + imple) + FW↵

http://www.spoj.com/problems/HOLI/ (4) //VERY NICE: 2*Distances from centroids ↵

</spoiler>↵

<spoiler summary="coloring">↵

http://codeforces.com/contest/741/problem/C 6↵

11331 UVA (4)↵

http://codeforces.com/contest/664/problem/D 4↵

</spoiler>↵

<spoiler summary="combinatorics">↵

http://codeforces.com/contest/52/problem/B (4) //[NICE][PREPROCESS][ROTATION]↵

3917 //Grid tiling [fancy approximation fomula]↵

http://codeforces.com/contest/760/
submission/24101933problem/F

https://devskill.com/CodingProblems/ViewProblem/61↵

https://devskill.com/CodingProblems/ViewProblem/255↵

UVA 10918↵

UVA 12576↵

UVA 1118 //Parity↵

http://www.spoj.com/problems/HLP_RAMS/ //Comb parity↵

Project Euler #78: Coin partitions //Partition function↵

http://www.spoj.com/problems/MAIN75/ //DP #of trees↵

12001 UVA (3)↵

12034 UVA (4)↵

11719 UVA (5)↵

11798 UVA (5)↵

11282 UVA (4) //dearrangement↵

11174 UVA (4)↵

http://codeforces.com/contest/666/problem/C 7↵

http://www.spoj.com/problems/JOKER1/ 3 prod(Ai-i)↵

http://www.spoj.com/problems/ANTP/ //4↵

http://codeforces.com/contest/645/problem/E (5) //formula: A[i]=Sum(A)+1↵

http://www.spoj.com/problems/SPCE/ (5) // N^{K-2}*Prod(comp_size)↵

http://codeforces.com/contest/785/problem/D (5) // F'(' C"(+)-1","("↵

13184 UVA (3)↵

http://codeforces.com/contest/816/problem/D (5) // Observation↵

13214 (4) //OEIS? : C(N+M-2,N-1)↵

http://codeforces.com/contest/844/problem/B (2) //Easy &mdash; pro prvaky↵

http://www.spoj.com/problems/JOSWAP/ (3) //Frequence array↵

http://www.spoj.com/problems/UCV2013E/ (4) //NICE&EASY: Choose steps to direction↵

http://www.spoj.com/problems/PARCARD1/ (4) //Partition function (raw)↵

http://www.spoj.com/problems/GOODB/ (2) //Easy (NICE): Choose [order]↵

http://www.spoj.com/problems/LOOPEXP/ (4) //A000254/N!↵

http://www.spoj.com/problems/DTPOLY/ (5) //DP might work too↵

http://www.spoj.com/problems/DTPOLY2/ (7) //Harder version of above (NICE but hell)↵

http://www.spoj.com/problems/HC12/ (3) //NICE &mdash; Sort + C(i,K-1)*A[i]↵

http://www.spoj.com/problems/STONE2/ (4) //NICE &mdash; Mostly DP [INVERSION][FACTORIAL]↵

http://www.spoj.com/problems/MAIN8_D/ (5) //NICE &mdash; Suffixes/Prefixes (same add 2^i)↵

http://www.spoj.com/problems/ITRIX_E/ (4) //VERY NICE &mdash; #Nonattacking 2-queens↵

http://www.spoj.com/problems/MAXSUB/ (3) //NICE &mdash; Subsets made of zeroes↵

http://www.spoj.com/problems/SKYLINE/ (3) //Catalan numbers [weird modulo &mdash; care]↵

http://codeforces.com/contest/26/problem/D (5) //Division of two combintion numbers [NI:/]↵

http://codeforces.com/contest/872/problem/E (6) // Prod:Sum(C(DistLines,CompSize))↵

</spoiler>↵

<spoiler summary="constructive">↵

http://codeforces.com/contest/8
02/problem/H (6) //We can do "N+k" by adding a letter p+k*x+u+xx↵

http://codeforces.com/contest/12/problem/E (5) //g[i][j]=1+(i+j)%(N-1) [+/-]↵

http://codeforces.com/contest/22/problem/C (4) //Start and then clique without v (+ random)↵

http://codeforces.com/contest/26/problem/C (5) //make Even*Even: do by 2*2 fields↵

http://codeforces.com/contest/41/problem/E (4) //[NICE][CN/2,N/2]↵

</spoiler>↵

<spoiler summary="dfs">↵

5/problem/A (3) //MODULO / SHIFT↵

http://codeforces.com/contest/81/problem/D (3) //NICE &mdash; MAX(N/2) &mdash; even/odd↵

http://codeforces.com/contest/63/problem/D (3) //NICE[GO BY LINES][4 WAYS B/D ODD/EVEN]↵

http://codeforces.com/contest/42/problem/C (4) //Constructive works too but random is fine :)↵

http://codeforces.com/contest/43/problem/D (3) //NICE &mdash; Easy to see [implementation]↵

http://codeforces.com/contest/53/problem/C (2) //EASY [B/E Alternate]↵

http://codeforces.com/contest/877/problem/C (3) //NICE 3*Alternative↵

http://codeforces.com/contest/802/problem/H (6) //We can do "N+k" by adding a letter p+k*x+u+xx↵

http://codeforces.com/contest/12/problem/E (5) //g[i][j]=1+(i+j)%(N-1) [+/-]↵

http://codeforces.com/contest/22/problem/C (4) //Start and then clique without v (+ random)↵

http://codeforces.com/contest/26/problem/C (5) //make Even*Even: do by 2*2 fields↵

http://codeforces.com/contest/41/problem/E (4) //[NICE][CN/2,N/2]↵

http://codeforces.com/contest/78/problem/B (2) //NICE &mdash; last 3 and then rest in modulo↵

</spoiler>↵

<spoiler summary="dfs">↵

http://codeforces.com/contest/884/problem/C (3) //[EASY][PERMUTATIONS][SORTING]↵

http://codeforces.com/contest/883/problem/G (4) //Greedy picking↵

http://codeforces.com/contest/60/problem/B (3) //3D Flood-Fill [NICE][EASY]↵

http://codeforces.com/contest/60/problem/C (4) //[VERY NICE][BF]//Not many real possibilities

https://devskill.com/CodingProblems/ViewProblem/3↵

https://devskill.com/CodingProblems/ViewProblem/17↵

https://devskill.com/CodingProblems/ViewProblem/118 //Kind-of↵

657 &mdash; The die is cast [UVA]↵

12186 UVA (3)↵

http://codeforces.com/contest/734/problem/E (5)↵

http://codeforces.com/contest/727/problem/A (3)↵

http://codeforces.com/contest/723/problem/E (6)↵

http://codeforces.com/contest/709/problem/E (6)↵

http://codeforces.com/contest/710/problem/E (4)↵

http://codeforces.com/contest/758/problem/E (8)↵

11323 UVA (5)↵

http://codeforces.com/contest/760/problem/B (3)↵

http://codeforces.com/contest/761/problem/E (6)↵

http://codeforces.com/contest/638/problem/B (3) //connect cons. letters↵

http://codeforces.com/contest/638/problem/C (4) //greedy idea &mdash; easy↵

http://codeforces.com/contest/638/problem/D (5) //spec-DAG articulatin↵

http://codeforces.com/contest/767/problem/C (4) ↵

http://codeforces.com/contest/781/problem/C (5)↵

http://codeforces.com/contest/794/problem/D (5) //NICE! Right done dfs↵

http://codeforces.com/contest/802/problem/K (5) //Slightly DP-like (NICE) TREE↵

http://codeforces.com/contest/813/problem/C (3) //Simply 2 DFS: NICE + EASY↵

http://codeforces.com/contest/841/problem/D (4) //DFS while tracking "next"↵

http://codeforces.com/contest/845/problem/G (5) //Keep track of cycles↵

http://codeforces.com/contest/844/problem/E (5) //Post-Order → line, Connect i → N-2: star↵

http://www.spoj.com/problems/CAC/ (5) //VERY NICE! &mdash; Find all cycles in cactus↵

http://codeforces.com/contest/849/problem/C (3) //State search by gauss↵

http://codeforces.com/contest/846/problem/E (5) //NICE: DFS + some overflow logic↵

http://www.spoj.com/problems/KOZE/ (3) //NICE: Floods↵

http://www.spoj.com/problems/RIOI_2_3/ (4) //DFS /OR/ BFS /OR/ DSU [NICE][EASY][BF]↵

http://www.spoj.com/problems/MAKEMAZE/ (3) //EASY &mdash; Simple dfs on grid ↵

http://codeforces.com/contest/861/problem/F (5) //VERY NICE: Modify dfs tree so it remains connected↵

http://www.spoj.com/problems/GHOSTS/ (3) //NICE &mdash; must remain dag after each QR↵

http://www.spoj.com/problems/AMR10J/ (5) //VERY NICE! &mdash; DFS+DP [DAG with cycles]↵

http://codeforces.com/contest/24/problem/A (2)//NICE [DFS-ON-CYCLE]↵

http://codeforces.com/contest/29/problem/C (3) //Find begining/end of line (graph)↵

http://codeforces.com/contest/29/problem/D (4) //Tree [implementation][simulation]↵

</spoiler>↵

<spoiler summary="digits">↵

http://www.spoj.com/problems/PR003004/ (4) //Simple digits count↵

http://codeforces.com/contest/770/problem/B (3) //max num max digsum↵

</spoiler>↵

<spoiler summary="dijkstra">↵

3850 [LA]↵

Gym 100625D [2013 Benelux Algorithm Programming Contest (BAPC 13)]↵

UVA 12950↵

Gym 100753A [2015 German Collegiate Programming Contest (GCPC 15) + POI 10-T3]↵

UVA 13030↵

UVA 1027↵

UVA 11377↵

http://codeforces.com/problemset/problem/843/D↵

11813 UVA↵

Gym 101242B [2016 ACM-ICPC World Finals] //+DP↵

Gym 100923B [2015 ACM National Contest Romania &mdash; Round 1]↵

UVA 11833↵

http://www.spoj.com/problems/EZDIJKST/en/↵

LightOJ 1019↵

UVA 13010 //+TS↵

2819 [LA]↵

UVA 12144↵

http://codeforces.com/contest/716/problem/D 7↵

12047 UVA 4↵

11514 UVA 4↵

http://codeforces.com/contest/757/problem/F 7↵

11338 UVA (4)↵

11374 UVA (4)↵

11097 UVA (4) //Divide to N*1000 nodes and go!↵

13172 UVA (5) //6*DJ per query + permutations↵

10816 UVA (4) //Easy Linear-Search by answer + DJ with path↵

http://codeforces.com/contest/827/problem/F 7 //Very nice &mdash; Even&Odd  ↵

http://www.spoj.com/problems/DELIVER/ (5) //Normalize coordinates + Optimalize↵

http://www.spoj.com/problems/CCHESS/ (4) //Dijkstra as knight↵

</spoiler>↵

<spoiler summary="divide_conquer">↵

http://codeforces.com/contest/817/problem/D (5) //Very nice NlogN↵

http://www.spoj.com/problems/DYNACON2/ (8) //Lesser hell &mdash; offline Nlog(N) /or/ NlogN^2↵

http://codeforces.com/contest/876/problem/F (5) //VERY NICE &mdash; Find greatest + next/back functions↵

</spoiler>↵

<spoiler summary="divisors">↵

http://codeforces.com/contest/75/problem/C (3) //[NICE][BS]↵

LightOJ 1068↵

LightOJ 1134↵

Project Euler #95: Amicable chains↵

NAJ0001 &mdash; Divisible Number Sum [SPOJ]↵

http://www.spoj.com/problems/LCMSUM/↵

https://www.hackerrank.com/contests/101hack38/challenges/easy-gcd-1/problem↵

UVA 13085↵

http://www.spoj.com/problems/CDRSANJ/↵

http://www.spoj.com/problems/DIVSEQ/↵

UVA 12154↵

UVA 13058↵

http://www.spoj.com/problems/EC_DIVS/↵

https://www.codechef.com/problems/CHEFKEY↵

http://codeforces.com/problemset/problem/671/C↵

Gym 101411G  [2009-2010 ACM-ICPC, NEERC, Western Subregional Contest]↵

http://codeforces.com/problemset/problem/831/F↵

http://codeforces.com/problemset/problem/839/D↵

12934 &mdash; Factorial Division [UVA]↵

UVA 10880↵

http://www.spoj.com/problems/PSTR/↵

http://codeforces.com/problemset/problem/27/E↵

[LA] 3014↵

UVA 12843↵

https://www.urionlinejudge.com.br/judge/en/problems/view/1164↵

http://codeforces.com/problemset/problem/803/F↵

10892 &mdash; LCM Cardinality↵

http://www.spoj.com/problems/GCDEX/↵

http://www.spoj.com/problems/INVDIV/↵

13083 &mdash; Yet another GCDSUM //ll↵

http://www.spoj.com/problems/IITKWPCF/ //ll↵

UVA 13185↵

UVA 13194↵

UVA 11388↵

http://www.spoj.com/problems/SAS002/↵

12425 &mdash; Best Friend↵

http://codeforces.com/problemset/problem/703/E↵

https://www.hackerearth.com/problem/algorithm/harry-gets-into-infy/↵

UVA 10830 //SUM↵

http://www.spoj.com/problems/DIVSUM/en/ //SUM↵

http://www.spoj.com/problems/AFS/ //SUM↵

UVA 11526 //SUM↵

</spoiler>↵

<spoiler summary="dp">↵

http://codeforces.com/contest/319/problem/C (6) //[NICE][CH-OPT]↵

http://www.spoj.com/problems/NKLEAVES/ (5) //[NICE][DC]↵

http://codeforces.com/contest/76/problem/D (4) //[BITS][OVERFLOW]↵

http://codeforces.com/contest/73/problem/C (4) //[NICE][EASY][TRY-ALL-LETTERS]↵

http://codeforces.com/contest/67/problem/C (4) //[NICE][LEAVENSTEIN]↵

http://codeforces.com/contest/67/problem/A (3) //[EASY][PRINTING][OTHER POSSIBLE WAYS]↵

http://codeforces.com/contest/55/problem/D (5) //[NICE][DIGITS][EFFICIENT]↵

http://codeforces.com/contest/56/problem/D (4) //String modification + printing [NICE]↵

http://codeforces.com/contest/58/problem/E (6) //[NICE][IMPLEMENTATION]↵

UVA 12181↵

https://devskill.com/CodingProblems/ViewProblem/21↵

https://devskill.com/CodingProblems/ViewProblem/37↵

https://devskill.com/CodingProblems/ViewProblem/71↵

https://devskill.com/CodingProblems/ViewProblem/103↵

https://devskill.com/CodingProblems/ViewProblem/107↵

https://devskill.com/CodingProblems/ViewProblem/115↵

https://devskill.com/CodingProblems/ViewProblem/126↵

https://devskill.com/CodingProblems/ViewProblem/131↵

https://devskill.com/CodingProblems/ViewProblem/134↵

https://devskill.com/CodingProblems/ViewProblem/174↵

https://devskill.com/CodingProblems/ViewProblem/186↵

https://devskill.com/CodingProblems/ViewProblem/201↵

https://devskill.com/CodingProblems/ViewProblem/338↵

https://devskill.com/CodingProblems/ViewProblem/368↵

https://devskill.com/CodingProblems/ViewProblem/392↵

https://devskill.com/CodingProblems/ViewProblem/399↵

https://www.hackerrank.com/contests/world-codesprint-5/challenges/mining //Opti↵

UVA 12915 //Opti↵

UVA 12524 //Opti↵

http://codeforces.com/problemset/problem/631/E //CH↵

https://devskill.com/CodingProblems/ViewProblem/6↵

https://devskill.com/CodingProblems/ViewProblem/11↵

11552 UVA (3)↵

12172 UVA (3)↵

4507 LA (5)↵

4510 LA (5) [+ geometry]↵

12181 UVA (6)↵

http://codeforces.com/contest/729/problem/F 6↵

http://codeforces.com/contest/735/problem/E 9↵

http://codeforces.com/contest/731/problem/E 5↵

12030 UVA (4)↵

http://codeforces.com/contest/721/problem/E 7↵

http://codeforces.com/contest/742/problem/D 4↵

12040 UVA (5)↵

http://codeforces.com/contest/712/problem/D 5↵

13162 UVA (6)↵

http://codeforces.com/contest/743/problem/E 6↵

11908 UVA (3)↵

11932 UVA (4)↵

http://codeforces.com/contest/745/problem/E (7)↵

11806 UVA (4)↵

http://codeforces.com/contest/747/problem/F (5)↵

11843 UVA (4)↵

http://codeforces.com/contest/752/problem/E (5)↵

http://codeforces.com/contest/703/problem/E (7)↵

11753 UVA (4)↵

11725 UVA (5)↵

http://codeforces.com/contest/722/problem/E (9)↵

http://codeforces.com/contest/760/problem/F (8)↵

11795 UVA (3)↵

11654 UVA (4)↵

11523 UVA (5)↵

11404 UVA (4)↵

11432 UVA (4)↵

11451 UVA (4) //C==20 mistake in statement↵

11301 UVA (4)↵

http://codeforces.com/contest/762/problem/D 5↵

11361 UVA (4) //digit DP↵

11365 UVA (7)↵

11391 UVA (4) //easy+implementation↵

11394 UVA (3)↵

11218 UVA (2)↵

11125 UVA (4) //slightly implementation↵

11076 UVA (3)↵

11081 UVA (4) //3 string subsequences (beware of fail)↵

http://codeforces.com/contest/678/problem/E (5) //bitset dp + probability↵

http://codeforces.com/contest/766/problem/C (4)↵

http://codeforces.com/contest/667/problem/C (3)↵

http://www.spoj.com/problems/MOVIFAN/ (3)↵

http://www.spoj.com/problems/ORDSUM23/ (3)↵

http://www.spoj.com/problems/DIVSEQ/ (4) //N^3 (but better...) works fine↵

http://codeforces.com/contest/633/problem/F (7) //Tree dp↵

http://www.spoj.com/problems/ADJDUCKS/ (4) sort + pick 2-3 continous O(N)↵

http://www.spoj.com/problems/JLNT/ (4) //pick 0 or 2 | 1e3*5e3↵

http://www.spoj.com/problems/TPCPALIN/ (5) //500^3 works (3rd countable)↵

http://www.spoj.com/problems/COLORSEG/ (4) //50^4==OK 50^4log(N)=TLE NICE↵

http://www.spoj.com/problems/POWERCAR/ (3) //1e3*1e3*2 &mdash; follow rules↵

http://www.spoj.com/problems/INGRED/ (5) //TSP-like [reduce + go]↵

http://www.spoj.com/problems/SPCO/ (5) //64*64*2 DP {OPT: prime O(1) + clear only half}↵

http://www.spoj.com/problems/WAYHOME/ (5) //NICE: 1) 1*1 b)12,1,**,2↵

http://www.spoj.com/problems/NFURY/ (2) //Minimal sum of squares↵

http://www.spoj.com/problems/GDIL/ (3) //combinatorics↵

http://codeforces.com/contest/791/problem/D (5) //Tree↵

http://codeforces.com/contest/791/problem/E (6) //V,K,X &mdash; pick any↵

http://codeforces.com/contest/789/problem/C (3)↵

13176 (4) //N^6↵

13179 (5) //NICE [Ath][Bth][TimeDiff]↵

http://codeforces.com/contest/796/problem/E (6) //NICE: N*P*K*K (WC can't happen!)↵

http://codeforces.com/contest/797/problem/E (4) //NICE: Almost BF-able (but care of low K)↵

http://codeforces.com/contest/793/problem/D (3) //NICE & EASY: begin/end/actual/USED↵

http://codeforces.com/contest/803/problem/E (4) //State search &mdash; many IF's (EASY)↵

http://codeforces.com/contest/805/problem/F (7) //NICE: DP on tree + fast BF + hack↵

http://codeforces.com/contest/808/problem/E (5) //NICE!↵

http://codeforces.com/contest/811/problem/C (4) //Precalculate + DP (greedy thinking)↵

10817 UVA 4 //Easy but slightly implementation↵

10859 UVA 4 //Nice &mdash; on tree .. but for a reason small constrains↵

10898 UVA 4 //Hash is lesser than 1e6 .. try everything↵

http://codeforces.com/contest/812/problem/B (3) //Not only DP, yet imho easiest ..many spec cases↵

http://codeforces.com/contest/813/problem/D (5) //VERY VERY NICE &mdash; N*N (none picked between a/b)↵

http://codeforces.com/contest/814/problem/E 5 //VERY NICE &mdash; Harder imple: Combinatorics↵

http://codeforces.com/problemset/problem/816/E (6) //NICE &mdash; Tree (hard 2C complexity)↵

http://codeforces.com/contest/837/problem/D (5) //NICE &mdash; yet kinda pain [must be iterative]↵

http://www.spoj.com/problems/AUT/ (4) //NICE &mdash; K is interesting ~ at most 1600↵

http://www.spoj.com/problems/GNYR04C/ (3) //Easy &mdash; Nice idea [Big→ Low approach]↵

http://www.spoj.com/problems/TIEROPE/ (4) //Process 2*L ~ otherwise pick BIG↵

http://www.spoj.com/problems/IITKWPCE/ (4) //Palindromes [efficiency!] &mdash; NICE!↵

IITKWPCD SPOJ (4) //+Slightly geometry ↵

UVA 1496 //[Steiner's Tree] Very Nice (8)↵

http://www.spoj.com/problems/LKS/ (3) //Classical knapsack↵

http://www.spoj.com/problems/UOFTAE/ (3) //Easy & Sympatic DP↵

http://www.spoj.com/problems/DCOWS/ (4) //Very NICE (sort + GO)↵

http://www.spoj.com/problems/FARIDA/ (3) //Easy & Sympatic ((u+1) | Price+(u+2))↵

http://www.spoj.com/problems/AU7_5/ (2) //EASY: dyn(n-1)+dyn(n-k-1)↵

http://www.spoj.com/problems/NAIVELOK/ (4) //NICE [depalindromisation] ↵

http://codeforces.com/contest/846/problem/C (4) //With print↵

http://www.spoj.com/problems/CNT_LUCK/ (4) //Number (binary) dp [NICE] {ull care 0-1}↵

http://www.spoj.com/problems/MAY99_4/ (3) //Almost combinatoric Sub and 0/1,1/0↵

http://www.spoj.com/problems/GEEKOUNT/ (4) //Number dp↵

http://www.spoj.com/problems/MUTDNA/ (4) // N*2 (turned?) [not sure if grd poss.]↵

http://www.spoj.com/problems/RIOI_3_2/ (5) //VERY NICE (easy imple &mdash; Number Theory thinking)↵

http://www.spoj.com/problems/MAXWOODS/ (3) //NICE [EASY][GRID]↵

http://www.spoj.com/problems/DIEHARD/ (3) //Easy &mdash; prolly solvable by greedy (but dp is easier)↵

http://www.spoj.com/problems/DCEPC810/ (4) //VERY VERY NICE &mdash; Subsequence 2pointers+2bools↵

http://www.spoj.com/problems/EQ2/ (4) //NICE: Digit + Carry (from back) &mdash; iff-party↵

http://www.spoj.com/problems/DCEPC501/ (3) //NICE & EASY↵

http://www.spoj.com/problems/NUMTSN/ (4) //NICE &mdash; Thinking or Opti↵

http://www.spoj.com/problems/GONE/ (4) //NICE & EASY [digits]↵

http://www.spoj.com/problems/RAONE/ (4) //NICE & EASY [digits] &mdash; almost similar as above↵

http://www.spoj.com/problems/STRSEQ/ (4) //VERY VERY NICE &mdash; Next-Function↵

http://www.spoj.com/problems/MYQ8/ (4) //VERY NICE &mdash; 3x3 tic-tac-toe [implementation]↵

http://codeforces.com/contest/859/problem/C (3) //Easy+Sympathic [PrefixSumOptional]↵

http://codeforces.com/contest/859/problem/D (4) //NICE [Probabilities]↵

http://www.spoj.com/problems/UNICA/ (4) //VERY NICE [Posibilities][Print][Classical]↵

http://www.spoj.com/problems/KOPC12H/ (4) //NICE Digit-DP↵

http://www.spoj.com/problems/DRACULA/ (4) //NICE Digit-DP (Both sides) &mdash; iterate by sum↵

http://www.spoj.com/problems/ABCPATH/ (3) //DP over dfs (maybe without dp works too?)↵

http://www.spoj.com/problems/BEHAPPY/ (2) //Easy one &mdash; low constraints↵

http://www.spoj.com/problems/STRCOUNT/ (4) //No input (over bits)↵

http://codeforces.com/contest/855/problem/B (2) //prolly not even necessary↵

http://codeforces.com/contest/855/problem/C (4) //dp on tree↵

http://codeforces.com/contest/855/problem/E (5) //VERY NICE &mdash; Digits & Bitmask & Query (learning!)↵

http://www.spoj.com/problems/PAINTWAL/ (6) //VERY NICE &mdash; Imho hard (opti could beat)↵

http://www.spoj.com/problems/ADFRUITS/ (3) //Very simple (substring == subsequence)↵

http://www.spoj.com/problems/MAIN113/ (2) //NICE but somehow too low constraints↵

http://www.spoj.com/problems/MAIN112/ (4) //NICE &mdash; Bitmask ↵

http://codeforces.com/contest/864/problem/E (5) //VERY NICE &mdash; Sort ↵

http://www.spoj.com/problems/NOVICE63/ (4) //NICE -On digits (binary)↵

http://www.spoj.com/problems/TUG/ (3) //NICE + Observation {N>100 == YES}↵

http://www.spoj.com/problems/DOMINO1/ (4) //Used map to solve it↵

http://www.spoj.com/problems/NY10E/ (2) //Easy dp↵

http://www.spoj.com/problems/MAIN72/ (3) //Easy knapsack↵

http://www.spoj.com/problems/NOVICE43/ (2) //Unbelievably low constraints↵

http://codeforces.com/contest/598/problem/E (4) //N^5 strategy works fine [VERY NICE]↵

http://www.spoj.com/problems/CHAIR/ (3) //Maybe combinatorics too?↵

http://www.spoj.com/problems/ACPC10D/ (3) //NICE &mdash; DAG traversal↵

http://www.spoj.com/problems/CPCRC1C/ (4) //Digits dp (return pair)↵

http://www.spoj.com/problems/BORW/ (3) //Inc+Dec sequence (small array)↵

http://codeforces.com/problemset/problem/18/E (5) //VERY NICE {no need for second iteration}↵

http://codeforces.com/contest/2/problem/B (5) //NICE &mdash; 2/5 are in-fact independent↵

http://codeforces.com/contest/4/problem/D (3) //Classical [FW works too] XY > xy↵

http://codeforces.com/contest/6/problem/D (4) //NICE (N^4)↵

http://codeforces.com/contest/321/problem/E (7) //VERY NICE &mdash; D&C Trick↵

http://codeforces.com/contest/868/problem/F (8) //VERY VERY NICE  D&C Trick &mdash; With MO Principal↵

http://codeforces.com/contest/8/problem/C (5) //NICE &mdash; Masks [N*2^N]↵

http://codeforces.com/contest/868/problem/E (8) //VERY NICE &mdash; HARD &mdash; on tree↵

http://codeforces.com/contest/10/problem/D (4) //LCIS [NICE]↵

http://codeforces.com/contest/13/problem/C (5) //NICE [sorting][only elements from array]↵

http://codeforces.com/contest/17/problem/C (5) //[NICE][iterative-sparse][+idea]↵

http://codeforces.com/contest/19/problem/B (4) //Knapsack (after good look)↵

http://codeforces.com/contest/30/problem/C (4) //Probabilities + (slight)GEO↵

http://codeforces.com/contest/31/problem/E (4) //[NICE]↵

http://codeforces.com/contest/41/problem/D (4) //With printing↵

</spoiler>↵

<spoiler summary="dsu">↵

http://codeforces.com/contest/87/problem/D (5) //[VERY NICE][SORTING][COMPRES][DFS]↵

http://codeforces.com/contest/884/problem/E (5) //[VERY NICE][MEMORY SPARSE]↵

http://codeforces.com/contest/60/problem/D (6) //[NICE][Pythagorean Triples][Gen over max!]↵

UVA 10947↵

UVA 12363↵

LA 3833 ↵

http://codeforces.com/problemset/problem/742/D  //+DP↵

UVA 10178↵

http://codeforces.com/contest/723/problem/F 7↵

13153 UVA (5)↵

13169 UVA (3)↵

11987 UVA (3)↵

11474 UVA (4)↵

http://www.spoj.com/problems/BTCODE_G/↵

http://codeforces.com/problemset/problem/691/D↵

Gym 101174K [2016-2017 ACM-ICPC Southwestern European Regional Programming Contest (SWERC 2016)]↵

UVA 10583↵

LightOJ 1003↵

http://codeforces.com/problemset/problem/731/C↵

UVA 793 ↵

UVA 11966↵

https://www.codechef.com/problems/COZIC↵

3939 [LA]↵

UVA 11503↵

http://codeforces.com/problemset/problem/755/C↵

UVA 1395↵

http://codeforces.com/contest/687/problem/D 6↵

http://codeforces.com/contest/680/problem/E 7 //+precalculation/brute force↵

http://codeforces.com/contest/766/problem/D 5↵

http://www.spoj.com/problems/LEXSTR/ (3) //Nice na stringu↵

http://codeforces.com/contest/805/problem/C 3 //NICE (dijkstra like :P)↵

http://www.spoj.com/problems/IITKWPCI/ (3) //VERY NICE ↵

http://www.spoj.com/problems/FRNDCIRC (3) //Classical DSU (NICE for practice)↵

http://www.spoj.com/problems/FOXLINGS/ (3) Easy &mdash; just renumbering↵

http://www.spoj.com/problems/SHAHBG/ (2) //DSU not needes (simulated by array)↵

http://codeforces.com/contest/598/problem/D (3) //Can be solved with DFS too↵

http://codeforces.com/contest/9/problem/E (4) //Making one big cycle↵

http://codeforces.com/contest/25/problem/D (4) //Could be done linear too↵

http://codeforces.com/contest/28/problem/B (4) //NICE [imho bad statement]↵

http://codeforces.com/contest/876/problem/D (4) //DSU adjacent + visited↵

http://codeforces.com/contest/875/problem/F (6) //NICE &mdash; Maximum cactus-forest [kruskal-like]↵

</spoiler>↵

<spoiler summary="euler_function">↵

UVA 10299↵

UVA 10990↵

https://www.codechef.com/problems/SMPLSUM↵

https://www.codechef.com/problems/COZIE↵

http://www.spoj.com/problems/LCMSUM/↵

Gym 100975F [2003-2004 Petrozavodsk Summer Training Camp, Saratov SU Contest]↵

UVA 13132↵

http://www.spoj.com/problems/GCDEX/↵

UVA 12995↵

http://www.spoj.com/problems/TIP1/↵

UVA 11327↵

LightOJ 1007↵

http://www.spoj.com/problems/ETF/↵

Project Euler #72: Counting fractions↵

http://www.spoj.com/problems/DCEPCA03/↵

http://www.spoj.com/problems/NAJPWG/ 4 //Gauss-Euler↵

http://www.spoj.com/problems/DCEPC12G/ (5) //Do what is written there↵

http://www.spoj.com/problems/INVPHI/ (5) //Inverse euler↵

</spoiler>↵

<spoiler summary="euler_tour">↵

UVA 10735↵

http://codeforces.com/contest/21/problem/D (5) //[NICE][EulerTour+DP]↵

http://codeforces.com/contest/36/problem/E (6) //VERY NICE [4odd is hardest]↵

</spoiler>↵

<spoiler summary="factorization">↵

UVA 13067↵

Project Euler #108: Diophantine reciprocals I↵

http://www.spoj.com/problems/CHGROOM/↵

Gym 101370A [2009-2010 Summer Petrozavodsk Camp, Petr Mitrichev Contest 5]↵

http://codeforces.com/problemset/problem/837/E↵

http://www.spoj.com/problems/PSYCHOT/↵

http://www.spoj.com/problems/FACTDIV/↵

http://www.spoj.com/problems/NOSQ/↵

http://www.spoj.com/problems/FCDC/↵

http://www.spoj.com/problems/NFACTOR/↵

http://www.spoj.com/problems/ABA12D/↵

http://www.spoj.com/problems/PSTR/↵

http://www.spoj.com/problems/AMR11E/↵

http://www.spoj.com/problems/FACT1/↵

http://www.spoj.com/problems/FACT2/↵

https://www.hackerearth.com/problem/algorithm/gold-at-lolympics/↵

12005 UVA (7)↵

12062 UVA (6)↵

11960 UVA (3)↵

http://www.spoj.com/problems/FACTCG2/ (3)↵

http://www.spoj.com/problems/FACT0/ (4)↵

http://codeforces.com/contest/546/problem/D 5↵

http://codeforces.com/contest/222/problem/C 6↵

http://www.spoj.com/problems/COMDIV/ 3↵

http://www.spoj.com/problems/SINEGGS/ 3↵

http://www.spoj.com/problems/BDOI16B/ 4↵

http://www.spoj.com/problems/HG/ 4 //Map == OK↵

11099 UVA (3) //factor + recursion↵

13194 UVA (3) //factorize+generate /or just check↵

13191 UVA (6) //Pollard-Rho↵

http://codeforces.com/contest/818/problem/E (4) // Efficient + Two Pointers↵

http://codeforces.com/contest/831/problem/F (6) //MAGIC↵

http://codeforces.com/contest/839/problem/D (4) // Combinatorics + IE↵

http://www.spoj.com/problems/SAS002/ (5) //Find all divisors (big numbers)↵

http://www.spoj.com/problems/GCDS/ (4) //Lowest unused prime↵

http://www.spoj.com/problems/IITKWPCF/ (4) //Nonprime divisors of N/2↵

http://codeforces.com/contest/851/problem/D (4) //Properties of GCD + factor: NICE↵

http://www.spoj.com/problems/PTIME/ (3) //Low bounds &mdash; check each prime independently↵

http://www.spoj.com/problems/MAIN12B/ (3) //NICE [Factorization][Sort][Unique]↵

http://www.spoj.com/problems/AMR11E/ (2) //2664 is the biggest↵

http://www.spoj.com/problems/GCPC11A/ (4) //Very nice &mdash; factorize + divide N by powers↵

http://www.spoj.com/problems/AMR10C/ (3) //Maximum of factor-powers↵

</spoiler>↵

<spoiler summary="fenwick">↵

http://codeforces.com/gym/101047/problem/J [2D]↵

http://www.spoj.com/problems/MATSUM/ [2D]↵

https://devskill.com/CodingProblems/ViewProblem/300↵

http://codeforces.com/contest/707/problem/E 7 [2D]↵

http://codeforces.com/contest/749/problem/E 8↵

http://codeforces.com/problemset/gymProblem/101055/D 5 [2D]↵

11240 UVA (4)↵

http://codeforces.com/contest/459/problem/D (4) //[NICE][SWEEPING]↵

http://codeforces.com/contest/61/problem/E (4) //[NICE][CLASSICAL][2*FW][NORMALIZE]↵

http://codeforces.com/contest/669/problem/E 5 //fenwicks &mdash; sparse↵

http://codeforces.com/contest/777/problem/E 4 //MAXIMUM↵

http://www.spoj.com/problems/TULIPNUM/ 4 //inc &mdash; 1 nor+num|sum(A[B],A[E])↵

http://codeforces.com/contest/799/problem/C 3 //MAX FW (but possibly easier?)↵

http://codeforces.com/contest/831/problem/E 4 //MAP to get ORDER &mdash; FW == LIST↵

http://www.spoj.com/problems/SAS001/ (4) //Nice &mdash; number of inversions + 2P↵

http://www.spoj.com/problems/TPGA/ (4) //NICE &mdash; Lesser*(N-i-1)!↵

http://www.spoj.com/problems/SUMSUM/ (5) //Bit-by-Bit cnt 0/1↵

http://www.spoj.com/problems/AKVQLD03/ (3) //Classical fenwick &mdash; easy↵

http://www.spoj.com/problems/ZIGZAG2/ (6) //Very nice &mdash; FW + BS + DP↵

http://codeforces.com/contest/849/problem/E (7) //2D Fenwick / ST+TP [NICE]↵

http://www.spoj.com/problems/CRAYON/ (5) //VERY NICE [2*FW &mdash; begin + end]↵

http://www.spoj.com/problems/NITT8/ (4) //Norm. + Store indices in MAX-Fenwick [REVERSE] [VERY NICE]↵

http://www.spoj.com/problems/DCEPC705/ (4) //NICE! Sort + Fenwick↵

http://www.spoj.com/problems/DCEPC206/ (3) //NICE & EASY <or many other approaches>↵

http://www.spoj.com/problems/KOPC12G/ (4) //N Fenwick trees↵

http://www.spoj.com/problems/TRIPINV/ (4) //2xFenwick (triples counting)↵

http://codeforces.com/contest/597/problem/C (4) //[VERY NICE] 11*Fenwick↵

http://codeforces.com/contest/12/problem/D (4) //NICE [triplet-comparing][sort]↵

</spoiler>↵

<spoiler summary="fft">↵

UVA 12633↵

6886 &mdash; Golf Bot [LA]↵

http://www.spoj.com/problems/POLYMUL/en/↵

Gym 100960C [2015-2016 Petrozavodsk Winter Training Camp, Nizhny Novgorod SU Contest]↵

https://www.codechef.com/problems/APRPS↵

https://www.codechef.com/problems/POLYEVAL↵

http://www.spoj.com/problems/TSUM/ 5↵

13182 UVA 5 //ACTG hamming↵

http://codeforces.com/contest/827/problem/E (8) //MAGIC↵

http://www.spoj.com/problems/MAXMATCH/ 5 //abc hamming↵

</spoiler>↵

<spoiler summary="flow">↵

http://www.spoj.com/problems/FASTFLOW/en/ //Raw (no sauce)↵

http://codeforces.com/contest/78/problem/E (5) //NICE [Matching-like][+BFS]↵

4322 — Destroying the bus stations (Live Archive)↵

11380 — Down Went The Titanic (UVA) //Interesting grid problem↵

6395 — Surely You Congest (LA) //VERY NICE [slightly advanced]↵

7204 — Blood groups (LA)↵

http://codeforces.com/gym/100963 (Flame of Nucleus — F)↵

11167 — Monkeys in the Emei Mountain //Also harder (imho)↵

http://codeforces.com/problemset/problem/653/D (+BS)↵

13000 — VIP Treatment (+BS)↵

1242 — Necklace↵

https://www.deadline24.pl/assets/problemsets/dl24.elim.2017.B.en.pdf (DEADLINE 24 problem — not sure if it can be submited :O)↵

3487 — Duopoly (Near matching)↵

http://codeforces.com/problemset/problem/727/D↵

5418 — A Plug for UNIX (LA)↵

4957 — Fake scoreboard (LA) //If I remember well, other solutions was also possible↵

1155 — Power Transmission (LOJ) //(classical)↵

https://www.codechef.com/problems/ROBOTDAG //Ford-Fukherson↵

10804 — Gopher Strategy (UVA)↵

11506 — Angry Programmer (UVA) //Nodes division↵

10511 — Councilling (UVA)↵

563 — Crimewave↵

1306 — The K-League (UVA)↵

1345 — Jamie's Contact Groups↵

10092 — The Problem with the Problem Setter↵

Problem B. Roller Coaster Scheduling (GCJ — 2017)↵

259 — Software Allocation (UVA)↵

5905 — Pool construction (LA) //Imho harder↵

10480 — Sabotage↵

http://codeforces.com/contest/808/problem/F 6 //NICE &mdash; nontrivial (max matching with bigger flows)↵

http://codeforces.com/contest/847/problem/J 6 //Probably not flows &mdash; matching-like↵

</spoiler>↵

<spoiler summary="flow-matching-like">↵

3837 [LA] //Stable Marriage↵

UVA 1175 //Stable Marriage↵

11594 — All Pairs Maximum Flow (UVA)↵

http://www.spoj.com/problems/ADABLOOM/ //Maximum matching in general graph↵

11439 — Maximizing the ICPC //Maximum matching in general graph↵

1376 — Animal Run //Max flow on planar graph (Dual == shortest path over edges)↵

10989 — Bomb, Divide and Conquer //Stoer-Wagner — global cut↵

</spoiler>↵

<spoiler summary="floyd-warshall">↵

10724 UVA↵

UVA 117↵

http://codeforces.com/problemset/problem/21/D↵

UVA 1198↵

LightOJ 1086 //+DP↵

http://www.spoj.com/problems/INGRED/ //+DP↵

UVA 10048↵

UVA 125↵

Gym 101223C [2017 Facebook Hacker Cup, Round 1] //+DP↵

LightOJ 1221↵

UVA 423↵

UVA 12179 //+DP↵

UVA 1416↵

UVA 1233 ↵

UVA 10793↵

10099 UVA↵

UVA 869↵

LightOJ 1174↵

http://www.spoj.com/problems/ARBITRAG/ //Other algos shall work too ↵

13211 UVA (5) //NICE &mdash; FW adding states↵

http://www.spoj.com/problems/ROHAAN/ (3) //Classical↵

http://codeforces.com/contest/25/problem/C (4) //Adding new edges .. need FW principal↵

http://codeforces.com/contest/33/problem/B (3) //NICE [dijkstra could work too]↵

</spoiler>↵

<spoiler summary="friedvaldAlgorithm">↵

4956 [LA]↵

</spoiler>↵

<spoiler summary="game_theory">↵

http://codeforces.com/contest/88/problem/E (5) //[VERY NICE][PREFIX-XOR][NIMBERS][SQRT][MATH]↵

http://codeforces.com/contest/69/problem/D (4) //[NICE][DP] Reflection can be ignored↵

http://codeforces.com/contest/55/problem/C (4) //[NICE] Size of piece from border↵

http://codeforces.com/problemset/problem/255/E --MEX↵

https://devskill.com/CodingProblems/ViewProblem/91↵

https://devskill.com/CodingProblems/ViewProblem/364↵

Project Euler #96: Su Doku //Sudoku↵

11859 UVA 4↵

11863 UVA 4↵

11892 UVA 3 //Probably solved by many↵

11534 UVA 5↵

http://www.spoj.com/problems/VECTAR11/ 4 //Nsqrt(N) passes [with break]↵

http://codeforces.com/contest/768/problem/E (4) //NICE &mdash; Grundy↵

http://www.spoj.com/problems/SYNC13C/ (4) //2*DP {maybe not seeing sth}↵

http://codeforces.com/contest/787/problem/C (4)↵

http://codeforces.com/contest/794/problem/C (3) //Find optimal strategy: choose back/front↵

http://codeforces.com/contest/794/problem/E (5) //NICE Find stategy: Even/Odd↵

http://www.spoj.com/problems/GAMEMVS/ (4) //Nimbers (Ai^X)<=Ai↵

http://www.spoj.com/problems/PLAYGAME/ (3) //Check pattern↵

http://www.spoj.com/problems/CHAOS_CC/ (4) //VERY NICE [nimbers]↵

http://codeforces.com/contest/851/problem/E (5) //Very nice [nimbers] [bitset]↵

http://www.spoj.com/problems/CHGROOM/ (4) //+Factorisation [NICE & Easy]: Win unless 2 prime factors↵

http://www.spoj.com/problems/EALP1/ (4) //NICE ~ Possible Moves of NIM↵

http://www.spoj.com/problems/GAME3/ (4) //VERY NICE &mdash; pattern watching [A145812]↵

http://www.spoj.com/problems/GAME2/ (5) //VERY NICE &mdash; https://community.topcoder.com/tc?module=Static&d1=match_editorials&d2=srm338 (CAKE)↵

http://www.spoj.com/problems/CF36D/ (5) //Pattern watching (care for 1)↵

http://codeforces.com/contest/15/problem/C (4) //VERY NICE [XOR: A,1,A+1,0..repeat]↵

http://codeforces.com/contest/39/problem/E (4) //Slightly [DP][MATH][ROUNDING]↵

</spoiler>↵

<spoiler summary="gauss">↵

12910 &mdash; Snakes and Ladders [UVA]↵

UVA 10828↵

http://codeforces.com/gym/100923/problem/C↵

4963 [LA]↵

UVA 12849↵

Gym 100962A [2015-2016 Petrozavodsk Winter Training Camp, Moscow SU Trinity Contest][NICE]↵

UVA 10109 [NICE][HARD-WORK]↵

</spoiler>↵

<spoiler summary="geometry">↵

http://codeforces.com/gym/101597/problem/B (3) //Simply  brute-force just the closest to points↵

http://codeforces.com/contest/70/problem/D (5) //Dynamic Convex Hull↵

https://icpc.kattis.com/problems/airport //Proposed by [user:tautsjasiunsas,2017-11-04]↵

https://www.hackerrank.com/contests/world-codesprint-7/challenges/elastic-rope/problem↵

https://devskill.com/CodingProblems/ViewProblem/20 [EASY]↵

UVA 10321 //Polygon intersection↵

UVA 11265 //Polygon point +/-↵

UVA 13112 //Polygon↵

10907 UVA [Area of polygon from a point]↵

3378 &mdash; Swamp Things [LA] &mdash; Maximum points on line↵

UVA 11768 //Discrete points↵

2542 [LA] //Arc size [formula]↵

UVA 1571 //As below [easier]↵

https://www.codechef.com/problems/ALLPOLY //[NICE] Point seeing polygon↵

http://www.spoj.com/problems/IITKWPCL/ //Point distance↵

UVA 11281 //circle~triangle↵

UVA 12921 //circle reconstruction↵

UVA 190 //circle from 3 points↵

UVA 12240 //pts>circle↵

UVA 438 //circle pt↵

LightOJ 1018 //Minimum # of lines through all pts [VERY NICE]↵

UVA 11008 //Similar as above↵

UVA 12830 //Biggest rectangle without points inside↵

UVA 11012 //Most distant points↵

UVA 1683 //Closest points↵

UVA 12389 //3D MH Closest Points↵

http://www.spoj.com/problems/AMR12C/ //Pt closest to all other points↵

http://www.spoj.com/problems/CLOPPAIR/ //Closest pair of points↵

UVA 10678 //Circles intersection↵

http://codeforces.com/problemset/problem/600/D //Circles intersection↵

LightOJ 1118 //Circles intersection↵

http://www.spoj.com/problems/CERC07C/en/ //Bounding circle↵

UVA-10005 //Bounding circle↵

2407 [LA] //Bounding Sphere↵

LightOJ 1120 //Rectangle's Union↵

LightOJ 1130 //Circle x Rectangle intersection↵

UVA 11177 //Circle x Convex Polygon↵

http://codeforces.com/problemset/problem/610/D //Lines intersections (axes parallel)↵

6263 [LA] //Pt in areas↵

LightOJ 1058 //# parallelograma↵

UVA 12931 //Common area of polygons↵

UVA 10301 //Intersecting circles↵

UVA 453 //Circles intersection↵

http://codeforces.com/problemset/problem/681/E //Circles intersection↵

UVA 920 //Lines intersecion (etc..)↵

UVA 12556↵

http://codeforces.com/problemset/problem/793/C //Intersection ans similar↵

UVA 11343 //Intersection of segments↵

UVA 866 //Intersection of segments↵

Gym 100190I [2011 ACM-ICPC East Central North America (ECNA 2011)] //Segment intersection↵

http://codeforces.com/gym/100917/problem/K↵

UVA 11686 //Segment intersection↵

LightOJ 1388↵

UVA 833 //Segment intersection↵

LightOJ 1196 //Points sides↵

UVA 10167 //Points sides↵

UVA 12818 //Arc & Point distance↵

http://www.spoj.com/problems/SICRANO/ //Point-line distance↵

http://codeforces.com/problemset/problem/614/C //Point-line distance↵

UVA 13117 //Point-line distance↵

UVA 12483 //Point-line distance↵

UVA 12173  //Point-line distance↵

UVA 10075 //Point distance on sphere↵

https://www.hackerrank.com/contests/booking-hackathon/challenges/nearby-attractions/problem //Pt sphr↵

UVA 535 //Point distance on sphere↵

UVA 10897 //Sphere tavelling↵

UVA 11817 //Sphere travelling↵

UVA 10316 //Sphere travelling↵

UVA 1469 //Fractions distance 3D↵

11930 ↵

12173 UVA 3↵

12194 UVA 4↵

11894 UVA 3↵

11769 UVA 7↵

11665 UVA 5↵

11509 UVA 4↵

11355 UVA 5↵

11265 UVA 6 //Nice one | polygon &mdash; cut/pt-check/area↵

11123 UVA 4 //Counting trapezoids↵

11177 UVA 6 //BS+Polygon/Circle intersection↵

11186 UVA 3 ↵

11008 UVA 5 //with DP → #intersected triangles↵

11012 UVA 5 //Nejvzdálenější body (Manhatton 3D)↵

11072 UVA 4 //Points v poly gonu↵

http://codeforces.com/problemset/problem/682/E 6 (biggest triangle)↵

http://codeforces.com/contest/672/problem/C 4 //easy &mdash; just think it up↵

http://codeforces.com/contest/667/problem/A 2 //vzorecky↵

http://codeforces.com/contest/793/problem/C 5 //EASY but beware of epsilons (NICE)↵

http://codeforces.com/contest/794/problem/B 2 //Can be done with BS↵

http://codeforces.com/contest/814/problem/D 5 //+DP on trees (NICE &mdash; but low geom.)↵

10750 UVA 3 //Closest points &mdash; try all pairs↵

http://codeforces.com/contest/820/problem/B 3 //Polygon angle find!↵

13213 UVA 5 //VERY NICE &mdash; Voronoi diagram (low constraints so not actually needed)↵

13215 UVA 3 //EASY &mdash; Sum areas and find side lengths↵

http://www.spoj.com/problems/IITKWPCC/ (5) //VERY VERY NICE &mdash; Nqrt(N)log(N)↵

http://www.spoj.com/problems/NNS/ (5) Closest points query [fake geometry] {__128}[NICE]↵

http://codeforces.com/contest/849/problem/B (3) //X-Product &mdash; side↵

http://www.spoj.com/problems/AMR12C/ (5) //Point closest to all other points (with speed)↵

http://www.spoj.com/problems/SICRANO/ (3) //Line-Point distance↵

http://www.spoj.com/problems/VCIRCLES/ (5) //Heavy geometrical ****↵

http://www.spoj.com/problems/CIRU/ (5) //Same as above [yet bigger constraints]↵

http://www.spoj.com/problems/THREETW1/ (4) //Fermat point search↵

http://www.spoj.com/problems/CLOPPAIR/ (4) //Closest pair of points↵

http://www.spoj.com/problems/MAXLN/ (2) //Some basic (4*r^2+.25)↵

http://www.spoj.com/problems/KOLICA/ (4) //VERY NICE [nasty iff party]↵

http://codeforces.com/contest/598/problem/C (4) //NICE ~ Precision! [ld]↵

http://codeforces.com/contest/18/problem/A (2) //EASY&FINE: Pythagoreas↵

http://codeforces.com/contest/40/problem/A (2) //[EASY][DISTANCE]↵

</spoiler>↵

<spoiler summary="graph">↵

2827 [LA] //3Coloring↵

2243 [LA] //3Coloring↵

5603 [LA] //Coloring↵

UVA 1658 //Shortest paths↵

UVA 12821 //Shortest paths↵

http://codeforces.com/contest/27/problem/D (5)↵

11387 (UVA) 4↵

http://www.spoj.com/problems/VFRIEND2/ (5) //Graph possible check↵

http://codeforces.com/contest/859/problem/E (4) //VERY NICE (2 cases: CYCLE [x2] / TREE [x(Size+1)]↵

http://codeforces.com/contest/847/problem/C (2) //Forest making Easy&Nice↵

http://codeforces.com/contest/863/problem/C (3) //Cycle in states↵

</spoiler>↵

<spoiler summary="greedy">↵

http://codeforces.com/gym/101597/problem/J (4) //[NICE][SWEEP]↵

http://codeforces.com/contest/76/problem/B (4) //[NICE][MATCHING-LIKE][2PTRS]↵

http://codeforces.com/contest/73/problem/B (4) //[IMPLEMENTATION][SORTING]↵

http://codeforces.com/contest/883/problem/K (4) //Nice &mdash; Two sweeps↵

http://codeforces.com/contest/49/problem/D (3) //NICE &mdash; 1010101 OR 0101010 [haming]↵

http://codeforces.com/contest/58/problem/C (4) //NICE &mdash; group trees by slopes↵

http://codeforces.com/contest/729/problem/D 3↵

http://codeforces.com/contest/729/problem/E 4↵

http://codeforces.com/contest/725/problem/D 4↵

http://codeforces.com/contest/725/problem/F 9↵

http://codeforces.com/contest/732/problem/E 5↵

http://codeforces.com/contest/727/problem/F 6↵

http://codeforces.com/contest/724/problem/D 5↵

http://codeforces.com/contest/723/problem/C 4↵

http://codeforces.com/contest/719/problem/B 2↵

http://codeforces.com/contest/712/problem/C 3↵

13152 UVA (4)↵

http://codeforces.com/contest/746/problem/E 5↵

http://codeforces.com/contest/746/problem/D 3↵

http://codeforces.com/contest/749/problem/C 3↵

11737 UVA (3)↵

11786 UVA (4)↵

11630 UVA (5)↵

11563 UVA (4)↵

11491 UVA (4)↵

11330 UVA (3)↵

11089 UVA (2)↵

http://codeforces.com/contest/884/problem/D (4) //PQ or Sort↵

http://www.spoj.com/problems/SQRMINSUM/ 3 //solve-able in O(N+M)-arrayqueue↵

http://www.spoj.com/problems/MSCHED/ 3 //sweep from back↵

http://www.spoj.com/status/ns=18780683 4 //all perm + A<B<C works↵

http://www.spoj.com/problems/NINJA7/ (3) //sort by diff↵

http://www.spoj.com/problems/NINJA2/ (4) //try all possib. (26)↵

http://codeforces.com/contest/767/problem/E (6)↵

http://codeforces.com/contest/637/problem/B (3) //NICE pro prvaky↵

http://codeforces.com/contest/777/problem/B (3) // -||-↵

http://codeforces.com/contest/777/problem/D (3) //just go from end↵

http://codeforces.com/contest/779/problem/C (3) //NICE pro prváky↵

http://www.spoj.com/problems/SPCU/ (2) //Easy &mdash; zamysleni (max int = index)↵

http://www.spoj.com/problems/LOPOV/ (4) //sort + queue (or just queue) NICE↵

http://codeforces.com/contest/792/problem/E (5) //T%S<=T/S + check proper↵

http://codeforces.com/contest/807/problem/E (5) //NICE &mdash; put asice P2 / rest &mdash; greedy from small↵

http://codeforces.com/contest/799/problem/E (5) //Many queues &mdash; but NICE↵

http://codeforces.com/contest/808/problem/C (3) //EASY↵

http://codeforces.com/contest/802/problem/B (4) //Priority by "next"↵

10850 UVA (4) //Queue a brute-force↵

http://codeforces.com/contest/813/problem/A (1) //Zahrivacka pro prvaky↵

10716 UVA (4) //NICE &mdash; always find closest pair↵

http://codeforces.com/contest/816/problem/C (3) //NICE &mdash; greater<lesser side↵

http://codeforces.com/contest/820/problem/D (5) //VERY NICE &mdash; O(N) -~- 5 events per number↵

http://codeforces.com/contest/818/problem/B (2) //Zahrivacka pro prvaky↵

http://codeforces.com/contest/822/problem/C (4) //Almost classical Sort+Queue↵

http://codeforces.com/contest/825/problem/C (2) //Nice & Easy↵

http://codeforces.com/contest/825/problem/D (3) //Update by modulo↵

http://codeforces.com/contest/835/problem/B (2) // Zahhrivacka pro prvaky↵

http://codeforces.com/contest/839/problem/B (3) //Nasty iffs &mdash; yet nice excersize↵

http://www.spoj.com/problems/PCPC12I/ (4) //Swipe MINIMUM from left/right [10^6-A[i] trick]↵

http://www.spoj.com/problems/AMR12I/ (3) //NICE a) MAX_SEG>=K b) (SEG_SIZE-1)/K+1↵

http://www.spoj.com/problems/BUSYMAN/ (2) //NICE&EASY &mdash; Sort + keep minimum↵

http://codeforces.com/contest/861/problem/C (3) //2+ but not same↵

http://www.spoj.com/problems/WORKB/ (3) //Simple "min" formula for each neighbor↵

http://codeforces.com/contest/864/problem/D (4) //VERY NICE &mdash; Frequency + unused↵

http://www.spoj.com/problems/ROADTRIP/ (4) //VERY NICE &mdash; Keeping last lesser↵

http://codeforces.com/contest/597/problem/B (3) //NICE [Classical]↵

http://www.spoj.com/problems/SHLIGHTS/ (4)↵

http://www.spoj.com/problems/MLK/ (3) //VERY NICE &mdash; Sum all prefix sums↵

http://codeforces.com/contest/867/problem/C (4) //NICE [IMPLE][2POINTERS][MID+EPS]↵

http://codeforces.com/contest/867/problem/E (5) //NICE [EASY-IMPLE][HARD-CONS]↵

http://codeforces.com/contest/18/problem/D (4) //+Big Integer↵

http://codeforces.com/contest/276/problem/D (4) //NICE &mdash; Find first mismatch bit (then 111...111)↵

http://codeforces.com/contest/3/problem/B (4) //Divide 1/2 [sort][2pointers]↵

http://codeforces.com/contest/3/problem/D (4) //?==) ..if open < 0: set max A-B to (↵

http://codeforces.com/contest/26/problem/B (4) // +1 ( | -1 ): -1, erase .. erase sum in the end↵

http://codeforces.com/contest/33/problem/A (2) //EASY [long-statement]↵

http://codeforces.com/contest/44/problem/E (2) //Try mins then try maxs↵

http://codeforces.com/contest/45/problem/D (3) //Priority-queue+'sort'↵

</spoiler>↵

<spoiler summary="hash">↵

Gym 101466E [2017 ACM-ICPC, Universidad Nacional de Colombia Programming Contest][NICE]↵

12012 UVA 4↵

http://codeforces.com/contest/727/problem/E 7↵

http://codeforces.com/contest/718/problem/D 8↵

11855 UVA 4↵

http://codeforces.com/contest/752/problem/D 5↵

http://codeforces.com/contest/825/problem/F 5 //String + Periods↵

http://codeforces.com/contest/835/problem/D 4 //Palindromes↵

http://www.spoj.com/problems/CF25E/ (5) //VERY NICE [IMPLE>CONCEPT]↵

http://codeforces.com/contest/7/problem/D (4) //Palindromes ↵

http://codeforces.com/contest/19/problem/C (4) //[NICE]: Not a string↵

</spoiler>↵

<spoiler summary="hull">↵

http://www.spoj.com/problems/GARDENHU/en/↵

2453 &mdash; Wall [LA]↵

UVA 13213↵

UVA 11096↵

Gym 100792G [2015-2016 ACM-ICPC, NEERC, Moscow Subregional Contest]↵

https://www.codechef.com/problems/KTHCON↵

http://codeforces.com/problemset/problem/605/C↵

UVA 218↵

UVA 11072↵

11168 UVA↵

UVA 12307↵

Gym 100963I [2007-2008 Summer Petrozavodsk Camp, Japanese Contest, 2007-08-29]↵

UVA 11243↵

UVA 10256↵

109 SCUD Busters↵

UVA 13024 [NICE]↵

UVA 10002↵

Gym 100886H [2015-2016 Petrozavodsk Winter Training Camp, Saratov SU Contest]↵

UVA 1139↵

UVA 681↵

UVA 811↵

https://www.codechef.com/problems/MGCHGEOM↵

UVA 11769 //3D↵

</spoiler>↵

<spoiler summary="chess">↵

http://codeforces.com/contest/42/problem/B (4) //NICE &mdash; Checkmate check↵

UVA 10748 //bfs↵

LightOJ 1143↵

https://www.hackerearth.com/practice/algorithms/greedy/basics-of-greedy-algorithms/practice-problems/algorithm/harry-and-ron-play-a-game-of-chess/↵

UVA 10196↵

http://www.spoj.com/problems/KNMOVE/↵

UVA 11352↵

http://www.spoj.com/problems/NAKANJ/ //BFS↵

LightOJ 1010↵

LightOJ 1171 //MM↵

2883 LA↵

UVA 439 ↵

http://www.spoj.com/problems/TRKNIGHT/ //??↵

2308 LA↵

http://www.spoj.com/problems/CCHESS/ //Dijkstra↵

http://codeforces.com/problemset/problem/630/H //[ROOKS][BIG][COMBINATORICS]↵

LightOJ 1005 //As above (but with real rooks)↵

LightOJ 1061 //Placing queens↵

UVA 11085↵

UVA 10094 //Queen placing [NICE][PATTERN]↵

https://devskill.com/CodingProblems/ViewProblem/383↵

11852  UVA (6)↵

http://www.spoj.com/problems/KLUG1/ (2) //Jumps of horse↵

http://www.spoj.com/problems/CODESPTD/ (5) //VERY NICE &mdash; DP [Queens]↵

http://codeforces.com/contest/3/problem/A (2) //Imple &mdash; Shortest path for king↵

http://codeforces.com/contest/38/problem/B (2) //NICE &mdash; Simple possition checking↵

</spoiler>↵

<spoiler summary="implementation">↵

http://codeforces.com/contest/90/problem/B (2) //No idea &mdash; just cycles↵

http://codeforces.com/contest/75/problem/A (1) //conversion↵

http://codeforces.com/contest/884/problem/B (1) //Simple sum +N-1↵

http://codeforces.com/contest/48/problem/A (1) //Very easy [fe. perm]↵

http://codeforces.com/contest/51/my (2) //Lex-lowest-string (|s|=4)↵

http://codeforces.com/contest/54/problem/A (2) //Single sweep↵

http://codeforces.com/contest/719/problem/C 3↵

http://codeforces.com/contest/747/problem/E 4↵

http://codeforces.com/contest/754/problem/C 5↵

11482 UVA (4)↵

11291 UVA (3)↵

11070 UVA (5)  //evaluation of expression↵

11074 UVA (2)↵

http://codeforces.com/contest/678/problem/B 2 //calendar days↵

http://codeforces.com/contest/643/problem/A 3 //easy &mdash; just simulate↵

http://codeforces.com/contest/770/problem/D 5 //easy &mdash; but pain &mdash; draw↵

http://codeforces.com/contest/789/problem/B 3 //simulate (mby twice)↵

13171 UVA (1)↵

10800 UVA (3)↵

http://codeforces.com/contest/828/problem/B 2 //EASY & NICE &mdash; just analysis↵

http://codeforces.com/contest/825/problem/B 2 //EASY & NICE &mdash; Piskvorky &mdash; pro prvaky↵

http://codeforces.com/contest/837/problem/B 2 //Just implementation↵

http://codeforces.com/contest/837/problem/C 2 //Some nasty iffs↵

http://codeforces.com/contest/845/problem/B 2 //Easy pro prvaky↵

http://codeforces.com/contest/845/problem/D 3 //Iffs &mdash; folow the rules↵

http://www.spoj.com/problems/UNIHW/ 4 //NICE (but many iffs)↵

http://codeforces.com/contest/5/problem/A (2) //Parsing↵

http://codeforces.com/contest/5/problem/B (3) //Output formating↵

http://codeforces.com/contest/6/problem/B (2) //Simply check by adjancecy vector + set↵

http://codeforces.com/contest/7/problem/A (1) //Oneinteresting if↵

http://codeforces.com/contest/8/problem/B (2) //Sample vectors + set/or/array↵

http://codeforces.com/contest/12/problem/A (1) //Find mirror by middle↵

http://codeforces.com/contest/16/problem/A (1) //Easy check of chars↵

http://codeforces.com/contest/21/problem/A (2) //Easy but nasty iff imple↵

http://codeforces.com/contest/31/problem/B (2) //Boring imple↵

http://codeforces.com/contest/34/problem/C (3) //Easy string parsing↵

http://codeforces.com/contest/41/problem/C (2) //String parsing↵

</spoiler>↵

<spoiler summary="inclusion-exclusion">↵

http://www.spoj.com/problems/KPRIMESB/ (4)↵

http://www.spoj.com/problems/IITKWPCH/ (4) //NICE &mdash; on bits↵

http://www.spoj.com/problems/SUBSET/ (5) //VERY NICE &mdash; 3^10 (^2 but not exactly) (+ sorting)↵

</spoiler>↵

<spoiler summary="interactive">↵

http://codeforces.com/contest/727/problem/C (2)↵

http://codeforces.com/contest/810/problem/D (4) //BS * 3 (same)↵

http://codeforces.com/contest/811/problem/D (4) //BFS &mdash; easy .. some ifs↵

http://codeforces.com/contest/835/problem/E (4) //NICE! Bitsets + Detect + XOR↵

http://codeforces.com/contest/844/problem/D (5) //NICE! Randomized algo↵

http://codeforces.com/contest/862/problem/D (4) //NICE! Find first + Binary Search↵

http://codeforces.com/contest/872/problem/D (4) //NICE! [no clue why it passed]↵

</spoiler>↵

<spoiler summary="isomorphism">↵

UVA 12489 //Tree↵

https://www.hackerrank.com/contests/hourrank-16/challenges/jenny-subtrees/problem↵

http://www.spoj.com/problems/DSUBTREE/ (5) //Isomorphism on trees (try all subsets)↵

http://www.spoj.com/problems/TREEISO/ (4) //Simple isomorphism of trees↵

</spoiler>↵

<spoiler summary="josephus">↵

UVA 151↵

UVA 1394↵

UVA 440↵

3803 [LA]↵

https://www.urionlinejudge.com.br/judge/en/problems/view/1030↵

UVA 12912↵

UVA 13114↵

11351 UVA (2)↵

http://www.spoj.com/problems/CLSLDR/ (4) //Muchas queries &mdash; go DP↵

</spoiler>↵

<spoiler summary="KMP">↵

UVA 12604↵

UVA 12467↵

UVA 11019↵

http://www.spoj.com/problems/NAJPF/ (4) //classical kmp &mdash; all patterns↵

http://codeforces.com/contest/808/problem/G (6) //with DP -harder↵

</spoiler>↵

<spoiler summary="lca">↵

http://www.spoj.com/problems/LCA/ //Easiest one &mdash; low constraints [practice]↵

http://www.spoj.com/problems/LCASQ/↵

https://devskill.com/CodingProblems/ViewProblem/141↵

UVA 12655↵

https://www.codechef.com/problems/PSHTTR↵

LightOJ 1162↵

Gym 100685G [2012-2013 ACM-ICPC, NEERC, Moscow Subregional Contest]↵

UVA 12533↵

https://www.codechef.com/problems/CLOSEFAR //But kinda more comples [ST]↵

http://codeforces.com/contest/733/problem/F 7↵

11354 UVA (4)↵

http://www.spoj.com/problems/POLICEMEN/ (3) //simple + small graph↵

http://www.spoj.com/problems/QTREE2/ (5) //very easy if bin. understrood↵

http://codeforces.com/contest/828/problem/F 7 // Differently MST / Outside↵

http://codeforces.com/contest/832/problem/D (5) //Classical + Depth /OR/ HLD +ST↵

http://www.spoj.com/problems/DRTREE/ (5) //NICE [finding ancestor + depths]↵

http://codeforces.com/problemset/problem/838/B (6) //VERY NICE [HLD + ET + ST]↵

http://www.spoj.com/problems/NTICKETS/ (4) //Maximum on path↵

http://www.spoj.com/problems/GRASSPLA/ (5) //HLD↵

</spoiler>↵

<spoiler summary="lcs_subsequence">↵

http://www.spoj.com/problems/MC/↵

UVA 10192↵

UVA 531↵

LightOJ 1110↵

UVA 12747 //Perm↵

http://www.spoj.com/problems/XMEN/ //Perm↵

UVA 10405↵

UVA 12511 //Increasing↵

UVA 10635 //Increasing↵

10949 UVA (6) &mdash; Hunt or Bit↵

http://www.spoj.com/problems/MC/ (3) //Classical↵

http://www.spoj.com/problems/LCS0/ (7) //Bit↵

</spoiler>↵

<spoiler summary="lct">↵

http://www.spoj.com/problems/DYNALCA/en/ //DYNAMIC LCA ↵

http://codeforces.com/gym/100460/problem/C↵

http://codeforces.com/gym/100960/problem/H↵

http://www.spoj.com/problems/DYNACON1/↵

</spoiler>↵

<spoiler summary="lis">↵

UVA 231↵

UVA 10131↵

2931 LA↵

http://www.spoj.com/problems/NDS/↵

UVA 481↵

http://www.spoj.com/problems/ELIS/↵

UVA 497↵

UVA 11790↵

http://www.spoj.com/problems/ALTSEQ/ 3 //solvable by FW in Nlog(N)↵

http://www.spoj.com/problems/VISIBLEBOX/ (4) //with multiset↵

http://www.spoj.com/problems/DOSA/ (5)↵

http://www.spoj.com/problems/CODERE3/ 3 //Low bounds LIS/LDS↵

http://www.spoj.com/problems/BRDGHRD/ 4 //lis (nondecreasing)↵

http://www.spoj.com/problems/GONESORT/ 4 //Permutation-lis + riddle statement↵

http://codeforces.com/contest/847/problem/B 4 //Multiple Lis's↵

http://codeforces.com/contest/67/problem/D (4) //[NICE][DOUBLE REMAP]↵

</spoiler>↵

<spoiler summary="matching">↵

http://www.spoj.com/problems/MATCHING/ //Raw (no sauce)↵

6234 — Tile Cut (LA)↵

10080 — Gopher II (UVA) //Easy — sympathic↵

11419 — SAM I AM (UVA) //Grid-Matching↵

http://codeforces.com/gym/101485 (Elementary Math — E) //Very nice principal [not that hard]↵

3673 — Black-White Grid (UVA) //Grid↵

12927 — Points Cover (UVA)↵

6851 — The Programmers (LA)↵

6887 — Book Club //NICE↵

6571 — It Can Be Arranged↵

12530 — Game of Tiles↵

http://codeforces.com/gym/100820 (Airport — A) //Nice one↵

http://codeforces.com/gym/100753 (Bounty Hunterr II — B) //VERY NICE — I refered multiple times to this principal↵

http://codeforces.com/gym/101408 (Cat vs Dog — C)↵

1171 — Knights in Chessboard (II) (LOJ) //Classical chess↵

12644 — Vocabulary↵

http://codeforces.com/gym/101047/problem/H↵

http://codeforces.com/problemset/problem/659/E↵

12972 — Cuban Challenge (UVA)↵

1201 — Taxi Cab Scheme (UVA)↵

12963 — Astragalus Nitidiflorus↵

6525 — Attacking rooks (LA)↵

3415 — Guardian of Decency (LA)↵

12159 — Gun Fight (UVA)↵

https://www.codechef.com/problems/CHEFYODA //Imho matching is not the crucial part here↵

12831 — Bob the Builder↵

http://codeforces.com/problemset/problem/831/D↵

11262 — Weird Fence↵

12549 — Sentry Robots↵

11138 — Nuts and Bolts↵

http://codeforces.com/contest/727/problem/D 4↵

11985 UVA (5)↵

http://www.spoj.com/problems/AMR12A/ (5) //VERY NICE [goophers + bonus] (BS)↵

http://www.spoj.com/problems/NITT4/ (4) //VERY NICE [Chessboard matching]↵

http://www.spoj.com/problems/SCPC11H/ (4)//NICE &mdash; Match those which fits inside↵

</spoiler>↵

<spoiler summary="matrix">↵

12045 UVA (4)↵

</spoiler>↵

<spoiler summary="matrix_exponentiation">↵

UVA 12653↵

LightOJ 1131↵

UVA &mdash; 12470↵

http://codeforces.com/problemset/problem/696/D↵

https://www.hackerrank.com/contests/mathemagic-bits/challenges/gp-on-fibonacci-matrix [accesable?]↵

https://www.hackerrank.com/contests/mathemagic-bits/challenges/degree-diameter-on-trees [accesable?]↵

LightOJ 1052↵

https://www.codechef.com/problems/KBIGNUMB↵

LightOJ 1160↵

LightOJ 1096↵

UVA 11486↵

http://codeforces.com/problemset/problem/718/C↵

LightOJ 1070↵

LightOJ 1132↵

http://codeforces.com/problemset/problem/621/E↵

Project Euler #114: Counting block combinations I↵

http://codeforces.com/problemset/problem/821/E↵

UVA 12593 ↵

https://www.codechef.com/AUG16/problems/SHAIKHGN //Not exactly but similar principle↵

11551 UVA (4)↵

11486 UVA (5)↵

10743 UVA (5) //A001169 [easy multi / hard to come with recurence]↵

http://codeforces.com/contest/821/problem/E (6) //Not trivial to come-up with matrix↵

http://www.spoj.com/problems/DCEPCA06/ (4) //NICE &mdash; 10x10 matrix↵

http://www.spoj.com/problems/GSWORDS/ (3) //NICE&EASY &mdash; 3-states "OO,OX,XO"↵

http://www.spoj.com/problems/TETRAHRD/ (4) //Easy + Sum↵

http://www.spoj.com/problems/NACCI/ (4) //Classical (N-Bonacci)↵

http://www.spoj.com/problems/JZPCIR/ (5) //VERY NICE: A137726↵

</spoiler>↵

<spoiler summary="mcmf">↵

http://codeforces.com/gym/100800 (Aqueduct Construction — A)↵

10806 — Dijkstra, Dijkstra.↵

12944 — Earthquake Disaster↵

https://www.codechef.com/problems/HOGON↵

http://codeforces.com/contest/863/problem/F (5) //VERY NICE↵

11613 UVA (6)↵

http://codeforces.com/contest/802/problem/C (8) //Nice but hard to see + negative↵

http://codeforces.com/contest/802/problem/N (5) //Easy but faster MCMF needed↵

http://codeforces.com/contest/818/problem/G (6) //NICE + MUCH Faster MCMF↵

http://www.spoj.com/problems/BNMT/ (7) //VERY NICE (some optimalisations needed + weird data set)↵

http://codeforces.com/contest/884/problem/F (6) //Alphabetical buckets↵

</spoiler>↵

<spoiler summary="median">↵

http://codeforces.com/contest/713/problem/C 7↵

http://www.spoj.com/problems/RMID2/ 4↵

http://www.spoj.com/problems/RMID/ 3 (as above just not so dynamic)↵

http://www.spoj.com/problems/EC_ESTA/ 4 //classical dynamic median↵

http://www.spoj.com/problems/DCEPCA09/ (6) //VERY NICE [MO +++ MEDIAN, MEAN, FREQ]↵

</spoiler>↵

<spoiler summary="meet_in_middle">↵

http://codeforces.com/contest/51/problem/E (6) //NICE[GRAPH][Cycles of length 5]↵

https://devskill.com/CodingProblems/ViewProblem/245↵

https://devskill.com/CodingProblems/ViewProblem/256↵

11851 UVA (5)↵

11465 UVA (5)↵

13207 UVA (4) //Straight-forward MIM↵

http://www.spoj.com/problems/COLOR_CC/ (4) //VERY NICE &mdash; div by partity (take lesser) → 8^6↵

</spoiler>↵

<spoiler summary="MO">↵

http://www.spoj.com/problems/FREQUENT/↵

http://codeforces.com/contest/86/problem/D (4) //[NICE][CLASSICAL]↵

http://codeforces.com/contest/877/problem/F (6) //[NICE][NORMALIZE]↵

http://codeforces.com/problemset/problem/687/D↵

http://codeforces.com/problemset/problem/617/E↵

http://www.spoj.com/problems/DCEPCA09/↵

http://www.spoj.com/problems/COT2/↵

https://www.codechef.com/problems/DISTNUM3 //Tree + Update↵

https://toph.ws/p/distinct-dishting //Not sure if still working??↵

https://www.codechef.com/problems/CHEFNUMK↵

https://www.hackerearth.com/problem/algorithm/harry-gets-into-infy-1/description/↵

http://www.spoj.com/problems/COT/ (7) //ON TREE [but very tight TLE]↵

http://www.spoj.com/problems/GOT/ (5) //ON TREE ↵

http://www.spoj.com/problems/CPAIR2/ (4) //MO + Fenwick [VERY NICE]↵

http://www.spoj.com/problems/KDOMINO/ (4) //NICE &mdash; Frequencies↵

</spoiler>↵

<spoiler summary="next">↵

http://codeforces.com/contest/92/problem/C (3) //[VERY NICE]↵

LightOJ 1157↵

https://www.codechef.com/problems/ASTRING↵

http://www.spoj.com/problems/MAIN8_E/↵

http://codeforces.com/problemset/problem/701/C ↵

http://www.spoj.com/problems/STRSEQ/ //+DP↵

http://codeforces.com/problemset/problem/762/C↵

http://codeforces.com/problemset/problem/724/D↵

http://www.spoj.com/problems/SUBSN/ //+BS↵

https://www.hackerrank.com/contests/world-codesprint-5/challenges/short-palindrome //+DP↵

</spoiler>↵

<spoiler summary="np-hard">↵

http://www.spoj.com/problems/JOHNNY/ //Not exact &mdash; points↵

http://codeforces.com/contest/839/problem/E (5) //NICE! Max-Clique↵

</spoiler>↵

<spoiler summary="number_rectangle">↵

UVA 10667 //Largest rectangle↵

UVA 10074 //Largest rectangle↵

UVA 836 //Largest rectangle↵

UVA 1330 //Largest rectangle↵

12192 UVA 5↵

http://codeforces.com/contest/729/problem/B 2↵

http://codeforces.com/contest/710/problem/C 4↵

11871 UVA 6↵

11617 UVA (3)↵

11573 UVA (4)↵

11499 UVA (5)↵

11230 UVA (4)↵

http://www.spoj.com/problems/JOCHEF/ (5) //NICE: Lagers rectange 0/1 O(N*M)↵

</spoiler>↵

<spoiler summary="number_theory">↵

http://codeforces.com/contest/93/problem/E (5) //[VERY NICE][DP][RECURSION]↵

http://codeforces.com/contest/86/problem/A (3) //[NICE] 50* is best (unless more digits)↵

http://codeforces.com/contest/83/problem/D (5) //[VERY NICE][PRIMES][BRUTE-FORE-2]↵

http://codeforces.com/contest/82/problem/A (2) //Simulation↵

http://codeforces.com/contest/74/problem/C (4) //gcd↵

http://codeforces.com/contest/76/problem/E (4) //Divide sumations [BF]↵

http://codeforces.com/contest/71/problem/C (3) //[EASY][NICE][BRUTE-FORCE][DIVISORS]↵

http://codeforces.com/contest/70/problem/A (2) //3^(N-1)↵

http://codeforces.com/contest/43/problem/C (2) //Moduly by 3 {0/2+min(1,2)}↵

http://codeforces.com/contest/50/problem/A (1) //[EASY]↵

http://codeforces.com/contest/61/problem/C (4) //Base conversion + roman↵

UVA 355 //bases conversion↵

2559 [LA] //Base conversion↵

https://www.codechef.com/problems/COPRIME3 //Cyka Möbius↵

http://www.spoj.com/problems/PSTR/ //Cyka Möbius↵

http://codeforces.com/problemset/problem/803/F //Cyka Möbius↵

https://devskill.com/CodingProblems/ViewProblem/23↵

http://codeforces.com/contest/731/problem/F 4↵

12031 UVA (8)↵

http://codeforces.com/contest/722/problem/F (8)↵

http://codeforces.com/contest/716/problem/C 4↵

http://codeforces.com/contest/711/problem/E (8)↵

http://codeforces.com/contest/710/problem/D (6)↵

13154 (UVA) 7↵

13166 (UVA) 5↵

11962 (UVA) 2↵

11718 UVA 3↵

11510 UVA (5)↵

11538 UVA (3) //good one &mdash; just math↵

11556 UVA (1)↵

http://codeforces.com/contest/757/problem/E (8)↵

http://codeforces.com/contest/758/problem/F (7)↵

11481 UVA (4)↵

11237 UVA (4) //Nice &mdash; seems like knapsbag but it it not↵

11155 UVA (4) //Almost as previous problem↵

11038 UVA (3) //counting digits on interval↵

http://codeforces.com/contest/763/problem/C (7)↵

11087 UVA (4) //Sums of two numbers divisible with <=500 (10^5)↵

http://codeforces.com/contest/678/problem/C 2 //LCM↵

http://codeforces.com/problemset/problem/665/F (8) //p^3 | p*q↵

http://www.spoj.com/problems/LCMSUM/ //Vzorec v knihovničce↵

http://www.spoj.com/problems/FRNDZND/ (2) // (size 1 == 1, else 0)↵

http://www.spoj.com/problems/EXPOR/ //bit-by-bit (+ formula)↵

http://www.spoj.com/problems/FACTDIV/ (5) //dyn-update of ans/factors GOOD↵

http://www.spoj.com/problems/PAIRDIV/ (6) //cyka möbius -_-↵

http://www.spoj.com/problems/FCDC/ (4) //keep factorized factorial ↵

http://www.spoj.com/problems/NTHPRIME/ (7) // BS + NumPrime GOOD!!↵

http://www.spoj.com/problems/DIVFACT3/ (7) // Sieve 10^8 + sqrt search↵

http://www.spoj.com/problems/DIVFACT4/ (8) // Prime count↵

http://codeforces.com/contest/776/problem/C (4) //segments div. by number↵

http://codeforces.com/contest/776/problem/E (6) //vypsat cisla: f(N)=Phi(N),g(N)=N↵

http://www.spoj.com/problems/PHT/ (2) //easy BS (NN+2N) mby math?↵

http://www.spoj.com/problems/GCDEX/ (7) //OEIS A006579  &mdash; enough [well imp]↵

http://www.spoj.com/problems/APS/ (3) //just sieve + generate↵

http://www.spoj.com/problems/WPC5I/ (3)//fc: C[a]!=C[b]:F[a]^max(C[a],C[b])↵

http://www.spoj.com/problems/SPEC_SET/ N→N/k→N/k/k↵

http://www.spoj.com/problems/DCEPC11B/ (5) //Wilson't theorem!↵

http://www.spoj.com/problems/FACTMULN/ (5) //each f[i]/c[i] separately↵

http://www.spoj.com/problems/SPCM/ (4) //just factorisation + prime check (10^12)↵

http://www.spoj.com/problems/TWOGAME/ (5) //gcd == Power of 3 => YES↵

http://www.spoj.com/problems/MKEQUAL/ (2) //Chceck if sum is divisible by N↵

http://www.spoj.com/problems/TIPTOP/ (3) //sqrt(N)==N? NICE!!↵

http://www.spoj.com/problems/PSYCHON/ (4) // fast factorisation↵

http://www.spoj.com/problems/ENIGMATH/ (1) // swap and div by gcd↵

http://www.spoj.com/problems/SNGPG/ (3) // prime gen + check↵

http://codeforces.com/contest/795/problem/A (2) //brute-force↵

http://codeforces.com/contest/801/problem/E (6) //NICE! &mdash; Clique-DAG + inversion↵

http://codeforces.com/contest/798/problem/C (4) //GCD == at the beginning OR 2↵

http://codeforces.com/contest/803/problem/C (3) //Only "low" K and just divisors↵

10830 (4) //simple add 2→ sqrt(N) + their mirrors↵

http://codeforces.com/contest/817/problem/A (2) //check division + parity↵

13209 UVA (3) //Simple simulation of division (+states rememberance)↵

http://codeforces.com/contest/834/problem/C (4) //Has cube-root + both num divisible by cuberoot↵

http://codeforces.com/contest/837/problem/E (5) //Factorisation + GCD attributes↵

http://www.spoj.com/problems/SUMMATION/ (3) //Number contribution: 2^(N-1)↵

http://www.spoj.com/problems/SECTORS/ (4) //Odd len OR sum of odd indices == sum of even↵

http://www.spoj.com/problems/IITKWPCM/ (6) //VERY NICE &mdash; Gauss's generalisation of Wilsons Theorem↵

http://www.spoj.com/problems/UCV2013A/ (4) //N*(N^L-1)/(N-1)↵

http://www.spoj.com/problems/KIMO1/ (4) //NICE &mdash; Adding/Subing by modulus↵

http://www.spoj.com/problems/AFS2/ (4) //Sum of divisort (sqrt(N)) &mdash; (+128int)↵

http://www.spoj.com/problems/FUNNUMS/ (4) //Permutations (get ith + guess ith)↵

http://www.spoj.com/problems/MAY99_3/ (3) //GCD↵

http://www.spoj.com/problems/PUCMM334/ (3) //Classical hats problem↵

http://www.spoj.com/problems/LCPC11B/ (4) //Factorize + count all subsets↵

http://www.spoj.com/problems/THREENUMBERS/ (2) //EASY & NICE [lcm]↵

http://www.spoj.com/problems/GAMES/ (2) //EASY&NICE &mdash; Go discrete (by 10^k) → 10^k/GCD↵

http://www.spoj.com/problems/SUBSHARD/ (4) //dig*10^sufix*(choose sufix)*^Prefix [VERY NICE]↵

http://www.spoj.com/problems/INVDIV/ (6) //Sum of divisors function + factorisation [NICE]↵

http://www.spoj.com/problems/JNEXT/ (2) //EASY &mdash; Zahřívačka pro prváky↵

http://www.spoj.com/problems/TSHOW1/ (3) //NICE &mdash; Almost as binary repre with 5/6↵

http://codeforces.com/contest/859/problem/B (2) //Easy by iteration↵

http://codeforces.com/contest/861/problem/A (2) //5,2 division [EASY]↵

http://www.spoj.com/problems/ABA12D/ (4) //NICE &mdash; Formula for sum divisors Prod(Sum(fac-powers))↵

http://www.spoj.com/problems/MAIN74/ (3) //Fibo's↵

http://www.spoj.com/problems/NOSQ/ (3) //Sieve + Digit check↵

http://www.spoj.com/problems/SQUAREV1/ (3) //NICE (but dumb code limit)↵

http://codeforces.com/contest/597/problem/A (1) //Simple if+2*Divide↵

http://www.spoj.com/problems/STREETR/ (3) //Easy [GCD]↵

http://www.spoj.com/problems/HPYNOSII/ (3) //<=1000 after first move↵

http://www.spoj.com/problems/HPYNOS/ (1) //Same as above &mdash; 1 number↵

http://www.spoj.com/problems/IITD4/ (3) //Brute-force [sieve-like]↵

http://www.spoj.com/problems/GIRLSNBS/ (2) //Some easy formula↵

http://www.spoj.com/problems/GUESSTHE/ (2) //NICE [EASY][LCM]↵

http://codeforces.com/contest/867/problem/B (2) //NICE [observation][1 2]↵

http://www.spoj.com/problems/NDIVPHI/ (4) //NICE &mdash; Multiple of lowest primes [BIG-INT]↵

http://www.spoj.com/problems/NDIVPHI2/ (5) //NICE &mdash; Same as above [bigger constraints]↵

http://codeforces.com/contest/6/problem/A (1) //Triangle check (4 pts)↵

http://codeforces.com/contest/869/problem/B (1) //Answer is usually 0↵

http://codeforces.com/contest/9/problem/C (2) //Bases (2→ 10)↵

http://codeforces.com/contest/20/problem/B (2) //Ax^2+Bx+C=0 (find roots)↵

http://codeforces.com/contest/27/problem/E (5) //[VERY NICE]: Factorisation+Recursion↵

http://codeforces.com/contest/32/problem/C (3) //DSU works too↵

http://codeforces.com/contest/872/problem/C (3) //NICE &mdash; Compose of 4 (mby one  6 or 9)↵

http://codeforces.com/contest/876/problem/B (3) //Group by modulo↵

</spoiler>↵

<spoiler summary="oeis">↵

12004 UVA 2↵

11273 UVA 5 //https://oeis.org/A001088↵

11077 UVA 3 //https://oeis.org/A094638↵

http://www.spoj.com/problems/VECTAR5/ 3 //https://oeis.org/A038721↵

http://www.spoj.com/problems/ESYRCRTN/ 2 //generate and see↵

http://www.spoj.com/problems/IITWPC4B/ 3 //http://oeis.org/A005044↵

http://www.spoj.com/problems/POLCONST/ (4) //A003401+Fermat Number (Prime)↵

http://www.spoj.com/problems/CUTCAKE/ (3) // pattern [1 22 333 4444 55555]↵

10872 UVA 3 //Alcuin's Sequence↵

http://www.spoj.com/problems/LOVINGPW/ (3) //A000788↵

http://www.spoj.com/problems/CBANK/ (3) //A000292 Tetrahedral numbers↵

http://www.spoj.com/problems/GUMATH2/ (4) //A000240 Modulo by MOD*2↵

http://www.spoj.com/problems/MATHII/ (4) //A006218  (Two formulas => sqrt(N))↵

http://www.spoj.com/problems/KOPC12B/ (4) //A002457 (factorial + factorial modular)↵

http://www.spoj.com/problems/YUMMY/ (4) //A006534 ↵

http://www.spoj.com/problems/FLWRS/ (4) //A002464↵

http://www.spoj.com/problems/RANJAN02/ (3) //A024023↵

http://www.spoj.com/problems/BOMARBLE/ (2) //A000326↵

http://codeforces.com/contest/57/problem/C (4) //A045992↵

</spoiler>↵

<spoiler summary="offline">↵

http://codeforces.com/problemset/problem/816/B //Easier ST↵

11266 UVA (6) //slightly knapsack || [NICE]↵

http://codeforces.com/contest/761/problem/F (7)↵

http://www.spoj.com/problems/UPDATEIT/ (2) //basic method↵

13189 UVA (4) //simulation + sort queries↵

http://www.spoj.com/problems/HAYBALE/ (3) //Basic sum + sort (segment tree would work too)↵

</spoiler>↵

<spoiler summary="palindromes">
http://codeforces.com/gym/101597/problem/H (6) //Offline 2D sum + geometry↵

</spoiler>↵

<spoiler summary="palindromes">↵

http://codeforces.com/contest/883/problem/H (3) //Make as least odd as possible↵

http://code-festival-2017-qualc.contest.atcoder.jp/tasks/code_festival_2017_qualc_c (3) //Similar to remove-dp, but greedy↵

http://code-festival-2017-qualc.contest.atcoder.jp/tasks/code_festival_2017_qualc_d (4) //DP with greedy thinking↵

http://codeforces.com/contest/59/problem/C (3) //Implementation [constructive]

UVA 13092 //manacher↵

http://www.spoj.com/problems/MSUBSTR/ //manacher↵

UVA 11888 //manacher↵

https://www.hackerrank.com/contests/101hack35/challenges/circular-palindromes //manacher↵

UVA 12378 //manacher↵

https://www.hackerrank.com/contests/world-codesprint-5/challenges/challenging-palindromes //SA↵

http://www.spoj.com/problems/NUMOFPAL/ //Palindromic Tree↵

http://codeforces.com/problemset/problem/245/H //# of palindromes [DP]↵

http://www.spoj.com/problems/ANAGR/ 2 //frequency + palindromes↵

http://www.spoj.com/problems/AMR12D/ (1) //Palindrome check //Zahrivacka pro prvaky↵

http://codeforces.com/problemset/problem/835/D //Hashing↵

</spoiler>↵

<spoiler summary="patter-matching">↵

11019 UVA (5)↵

</spoiler>↵

<spoiler summary="permutations">↵

http://codeforces.com/contest/844/problem/C 3 //NICE Permutations in array↵

http://codeforces.com/contest/48/problem/D (3) //NICE [frequency array]↵

http://codeforces.com/contest/56/problem/B (2) //Restore from 1 reverse [EASY]↵

</spoiler>↵

<spoiler summary="persistent_segment_tree">↵

http://codeforces.com/contest/813/problem/E (6) //Easy but hard data structure↵

</spoiler>↵

<spoiler summary="preprocess">↵

http://codeforces.com/contest/48/problem/B (2) //2D Prefix Sum [BF prolly works too]↵

http://codeforces.com/problemset/problem/761/F↵

UVA 10360 //2D Prefix Sum↵

UVA 983 //2D Prefix Sum↵

http://codeforces.com/contest/777/problem/C (4) //NICE↵

http://codeforces.com/contest/818/problem/C (4) //Prefix Sum↵

http://codeforces.com/contest/834/problem/B (2) //26 queries &mdash; NICE rozehrivacka pro prvaky↵

http://www.spoj.com/problems/RANGESUM/ (4) //NICE: Offline (delta) + Prefix Sum↵

http://www.spoj.com/problems/RANDG/ (3) //NICE [but too low bounds] [PrefixSum] [Try all indexes]↵

http://www.spoj.com/problems/HARSHAD/ (3) //Sieve + simple function↵

http://www.spoj.com/problems/PUCMM210/ (3) //Number theory (thinking not necessary)↵

http://www.spoj.com/problems/BCAKE/ (3) //Prefix sum of rectangle + N^4↵

http://www.spoj.com/problems/PAIRSUM/ (4) //VERY NICE &mdash; Prefix sum + Prefix PW sum↵

http://www.spoj.com/problems/MAIN111/ (3) //Sieve + Brute Force (answer in O(1))↵

http://www.spoj.com/problems/PLUSEVI/ (4) //NICE &mdash; There are not many of them↵

http://codeforces.com/contest/18/problem/C (2) //Prefix sum End==2*i↵

http://codeforces.com/contest/873/problem/B (2) //Search for same prefix (+/-1)↵

http://codeforces.com/contest/33/problem/C (4) //Prefix sum + Sweep from back + sweep from front↵

http://codeforces.com/contest/872/problem/B (3) //Sweep from both sides (RMQ works too)↵

</spoiler>↵

<spoiler summary="prime-count">↵

http://www.spoj.com/problems/NTHPRIME/↵

http://www.spoj.com/problems/DIVFACT4/↵

http://codeforces.com/problemset/problem/665/F↵

https://www.codechef.com/problems/CNTPRIME↵

http://www.spoj.com/problems/SUMPRIM1/↵

http://www.spoj.com/problems/SUMPRIM2/ [NO &mdash; hard]↵

https://www.hackerrank.com/contests/projecteuler/challenges/euler010/problem //easy↵

</spoiler>↵

<spoiler summary="prime-testing">↵

http://www.spoj.com/problems/PON/en/↵

http://www.spoj.com/problems/DAYOUT2C/en/ [EASY]↵

Project Euler #60: Prime pair sets↵

Project Euler #58: Spiral primes↵

Project Euler #131: Prime cube partnership↵

https://devskill.com/CodingProblems/ViewProblem/229↵

https://devskill.com/CodingProblems/ViewProblem/327↵

Gym 100753K [2015 German Collegiate Programming Contest (GCPC 15) + POI 10-T3]↵

Project Euler #130: Composites with prime repunit property↵

http://www.spoj.com/problems/ABA12A/ (3)↵

10871 UVA (3) //Easy &mdash; fermat not necessary↵

http://www.spoj.com/problems/POP1/ (4) //Fast primality testing (or somehow)↵

http://www.spoj.com/problems/POP2/ (5) //NICE &mdash; same as above (yet with ll)↵

http://www.spoj.com/problems/POP3/ (6) //same as above (yet with big)↵

http://www.spoj.com/problems/DCEPC203/ (6) //NICE [optimalisation]↵

http://www.spoj.com/problems/PRIMPERM/ (4) //NICE (next_perm + sieve)↵

</spoiler>↵

<spoiler summary="probability">↵

Gym 101064K [2016 USP Try-outs] //Birthday Paradox↵

11762 UVA (5)↵

11427 UVA (5)↵

11348 UVA (2)↵

http://codeforces.com/contest/768/problem/D (4) //With DP↵

http://www.spoj.com/problems/IITWPC4J/ (4) //with DP↵

10828 UVA (5) //Nice problem but bad statemend: Expected value of visits MC↵

10777 UVA (4) //NICE &mdash; yet solvable with DP↵

http://codeforces.com/contest/839/problem/C (3) //NICE & Easy => Tree↵

http://www.spoj.com/problems/ZCR/ (3) //Easy (+DP)↵

http://www.spoj.com/problems/IITKWPCN/ (2) //Easy &mdash; Odd/Eve (black balls)↵

http://codeforces.com/contest/846/problem/F (5) // Expected number of unique elements↵

http://www.spoj.com/problems/BTCODE_H/ (4) //DP (but main GROW is idea)↵

http://codeforces.com/contest/867/problem/D (5) //VERY NICE [DP]↵

http://codeforces.com/contest/24/problem/D (5) //VERY NICE [DP]+[TIME]↵

http://codeforces.com/contest/28/problem/C (4) //VERY NICE [DP]↵

</spoiler>↵

<spoiler summary="recursion">↵

http://codeforces.com/contest/68/problem/D (5) //[NICE] Keep max and kill branches↵

UVA 536 //Tree from dfs↵

UVA 12347 //BST from preorder↵

http://www.spoj.com/problems/GOC11A/ 4↵

13170 UVA (7) //heavy implementation &mdash; but NICE!↵

10854 UVA (3) //if/else↵

http://codeforces.com/contest/31/problem/D (4) //[NICE] Brute-force by recursion↵

http://codeforces.com/contest/36/problem/B (2) //[NICE][SIMPLE]↵

</spoiler>↵

<spoiler summary="RMQ">↵

http://codeforces.com/problemset/problem/514/D //+BS↵

http://codeforces.com/problemset/problem/872/B↵

http://www.spoj.com/problems/TNVFC1M/↵

https://devskill.com/CodingProblems/ViewProblem/19↵

http://codeforces.com/contest/713/problem/D 6↵

http://codeforces.com/contest/675/problem/E 5↵

http://www.spoj.com/problems/POSTERIN/ 5 //VERY NICE &mdash; Delete all minimas↵

http://www.spoj.com/problems/RPLN/ (3) //RMQ only↵

http://www.spoj.com/problems/CITY2/ (4) //RMQ + MAP [NICE][VAGUE STATEMENT]↵

http://www.spoj.com/problems/DIFERENC/ (4) //Solve separately (linear D&C)↵

http://codeforces.com/contest/863/problem/E (4) //OR some Queue / sorting↵

http://codeforces.com/contest/5/problem/C (4) //NICE &mdash; many other options↵

http://codeforces.com/contest/15/problem/D (5) //VERY NICE 2D RM  [sliding-windw][monotone-queue]↵

http://codeforces.com/contest/873/problem/E (5) //[NICE][Brute-Force + RMQ]↵

</spoiler>↵

<spoiler summary="rope">↵

http://www.spoj.com/problems/AROPE/ 4↵

http://www.spoj.com/problems/AROPE2/ 5 //same as above (+time)↵

</spoiler>↵

<spoiler summary="scc">↵

https://devskill.com/CodingProblems/ViewProblem/79↵

UVA 11838↵

UVA 247↵

UVA 13057↵

UVA 12645↵

UVA 11770↵

UVA 12926↵

UVA 11324↵

UVA 11709↵

UVA 12745↵

http://www.spoj.com/problems/TFRIENDS/ (4) //just scc size↵

http://www.spoj.com/problems/CAPCITY/ (4) //scc destination [WEAK TC]↵

http://codeforces.com/contest/22/problem/E (5) //[NICE][make it strongly connected][SRC>DST]↵

</spoiler>↵

<spoiler summary="segment_tree">↵

http://codeforces.com/contest/52/problem/C (4) //Easy [MIN]+[INCREASE]↵

http://codeforces.com/contest/56/problem/E (5) //[NICE][NORMALIZE][MAX]↵

http://codeforces.com/contest/877/problem/E (5) //[VERY NICE][EULER TOUR TREE]↵

https://devskill.com/CodingProblems/ViewProblem/283↵

https://devskill.com/CodingProblems/ViewProblem/315↵

http://codeforces.com/problemset/problem/756/C↵

http://codeforces.com/contest/739/problem/C (8)↵

http://codeforces.com/contest/718/problem/C (8)↵

http://codeforces.com/contest/750/problem/E (7)↵

http://codeforces.com/contest/759/problem/C (7)↵

11165 UVA (5)↵

http://codeforces.com/contest/763/problem/E (8) //VERY NICE &mdash; [non-trivial]↵

http://www.spoj.com/problems/BGSHOOT/ (5) //normalize &mdash; then easy↵

http://www.spoj.com/problems/KGSS/ (4)↵

http://codeforces.com/contest/765/problem/F (7) //VERY NICE &mdash; CASCADE↵

http://www.spoj.com/problems/GSS1/ (5) //Idea &mdash; then easy↵

http://www.spoj.com/problems/KQUERYO/ (5) //Seg-tree of vectors↵

http://codeforces.com/contest/633/problem/G (8) //EulerTree+Seg+Bitset↵

http://www.spoj.com/problems/NAJ0001/ (7) //10^8 int &mdash; memory (and worked)↵

http://www.spoj.com/problems/PRMQUER/ (5) //2 segment trees + sieve↵

http://www.spoj.com/problems/EC_DIVS/ (5) //dunno if intended↵

http://www.spoj.com/problems/DCEPC11I/ (5) //NICE &mdash; 1,2,3,4,5,.. inc↵

http://www.spoj.com/problems/QUE2/ (4) //kth number↵

http://codeforces.com/contest/785/problem/E (6) //Seg+Treap [and faster]↵

http://codeforces.com/contest/786/problem/B (6) //+Dijkstra↵

13183 UVA (6) //Merge-Sort-Tree [dunno]↵

http://codeforces.com/contest/803/problem/G (5) //VERY NICE!! &mdash; ST 10^9 + ST/RMQ 10^5↵

http://codeforces.com/contest/794/problem/F (7) //Digit by digit! (N*log(N)*100 ~passes,2017-10-19)↵

http://codeforces.com/contest/811/problem/E (6) //VERY NICE &mdash; DSU (easier Timofey + animals)↵

http://codeforces.com/contest/817/problem/F (7) //10^18 + MEX ~~ NICE yet problematic↵

http://codeforces.com/contest/816/problem/B (3) //Or offline trick makes it easier↵

http://codeforces.com/contest/834/problem/D (5) //+Dynamic Programming | NICE ↵

http://www.spoj.com/problems/SBO/ (5) //preLast→ last (-1), last→ now (+1) &mdash; VERY NICE↵

http://www.spoj.com/problems/GOODE/ (5) //NICE: Inversion + L-Mex↵

http://www.spoj.com/problems/CNTPRIME/ (3) //ST+Sieve (short range)↵

http://www.spoj.com/problems/SEGSQRSS/ (4) //NICE {weak data} ~~ SQRT works too↵

http://www.spoj.com/problems/MON2012/ (5) //NICE [Online][10^9 Range]↵

http://www.spoj.com/problems/PARSUMS/ (4) //But other approaches work too↵

http://www.spoj.com/problems/THRBL/ (4) //Simple SA &mdash; maximum on range <= A[a]↵

http://www.spoj.com/problems/HORRIBLE/ (3) //Totally classical↵

http://www.spoj.com/problems/MULTQ3/ (4)  //NICE (interesting operation)↵

http://www.spoj.com/problems/PERMPATT/ (4) //NICE [minimum][+IDEA]↵

http://codeforces.com/contest/869/problem/E (5) //NICE &mdash; 2D [random][XOR]↵

http://codeforces.com/contest/19/problem/D (5) //NICE [+BS][+SET] {bs not necessary}↵

</spoiler>↵

<spoiler summary="sequences">↵

11885 UVA 7 //Previous problem requested for statement↵

11522 UVA 3 //Trick &mdash; low numbers only :P↵

</spoiler>↵

<spoiler summary="sieve">↵

http://codeforces.com/contest/58/problem/B (3) //[NICE][GREEDY][LEAST PRIME FACTOR]↵

Project Euler #134: Prime pair connection //Segmented↵

11610 UVA (5)↵

11353 UVA (3)↵

http://www.spoj.com/problems/TDPRIMES/ (4)↵

http://www.spoj.com/problems/VECTAR8/ (3)↵

http://www.spoj.com/problems/NFACTOR/ (4)↵

http://www.spoj.com/problems/HS08PAUL/ (4) //simply generate↵

http://codeforces.com/contest/776/problem/B (3) //Easy &mdash; trict: PM-1/ELSE-2↵

http://www.spoj.com/problems/GGD/ (4) // N/lowestDiv*(lowestDiv-1)↵

http://codeforces.com/contest/822/problem/D (4) //DP + Lowest factor↵

http://www.spoj.com/problems/NGIRL/ (4) //Squares &mdash; Primes + BS == Easiest↵

http://www.spoj.com/problems/PTRI/ (5) //Very fast sieve necessary:/↵

http://www.spoj.com/problems/AFS/ (3) //Sum of divisort + DP↵

http://www.spoj.com/problems/BSPRIME/ (4) //Very fast sieve needed↵

http://www.spoj.com/problems/DCEPC505/ (4) //NICE &mdash; at most 10527450↵

http://www.spoj.com/problems/CUBEFR/ (3) //NICE &mdash; Sieve out k^3 numbers↵

http://www.spoj.com/problems/PRIMES2/ (8) //VERY NICE &mdash; Some hell-shit optimizing↵

http://codeforces.com/contest/26/problem/A (2) //Easy &mdash; many ways to solve it↵

</spoiler>↵

<spoiler summary="simulation">↵

http://codeforces.com/contest/92/problem/A (1) //Way too easy↵

http://codeforces.com/contest/88/problem/C (3) //[NUMBER THEORY]↵

http://codeforces.com/contest/84/problem/D (4) //Priority queue by min*size↵

http://codeforces.com/contest/79/problem/A (1) //Simulate rules↵

http://codeforces.com/contest/879/problem/A (1) //Iterate day-by-day↵

http://codeforces.com/contest/879/problem/B (3) //Either at most N^2 or the biggest element [NICE]↵

http://codeforces.com/contest/879/problem/D (4) //[NICE][Array elimination]↵

http://codeforces.com/contest/46/problem/A (2) //[EASY][MODULO]↵

http://codeforces.com/contest/46/problem/B (3) //[EASY][SEARCH-EACH-QUERY]↵

http://codeforces.com/contest/55/problem/A (2) //Simple (long) simulation↵

http://codeforces.com/contest/60/problem/A (1) //Moving LR bounds↵

12187 UVA (2)↵

http://codeforces.com/contest/724/problem/C 5↵

http://codeforces.com/contest/746/problem/C 3↵

11093 UVA (2)↵

http://codeforces.com/contest/768/problem/C (4)↵

http://www.spoj.com/problems/WRONG/ (5) //VERY NICE &mdash; precalculate from back, then go from front↵

http://codeforces.com/contest/864/problem/C (4) //Not nice &mdash; just iffs↵

http://www.spoj.com/problems/WAGE/ (3) //Simple Game Of Life Modification↵

http://codeforces.com/contest/6/problem/C (2) //Simple simulate from both sides↵

http://codeforces.com/contest/9/problem/B (2) //Simulate what is given (+ doubles)↵

http://codeforces.com/contest/11/problem/B (3) //sqrt(X) [diff must be even]↵

http://codeforces.com/contest/30/problem/A (2) //Simply simulate process [-1000→ 1000]↵

</spoiler>↵

<spoiler summary="sorting">↵

http://codeforces.com/contest/81/problem/C (3) //MATH[Lesser=greater][comparator]↵

http://codeforces.com/contest/53/problem/D (3) //Bubble sort↵

http://codeforces.com/contest/58/problem/D (4) //[BUCKET][GREEDY][STRING]↵

UVA 10810 //INV↵

UVA 11858 //INV↵

http://codeforces.com/problemset/problem/645/B //INV↵

UVA 10327 //INV↵

http://www.spoj.com/problems/BUBBLESORT/ //INV↵

UVA 11495 //INV [GAME]↵

http://www.spoj.com/problems/CODESPTB/ //INV↵

UVA 13212 //INV↵

http://codeforces.com/problemset/problem/749/E //INV↵

12189 UVA (3)↵

12196 UVA (4)↵

http://codeforces.com/contest/731/problem/D 7↵

11925 UVA (4)↵

11979 UVA (3)↵

http://codeforces.com/contest/747/problem/D (4)↵

11890 UVA (4)↵

http://www.spoj.com/problems/KAOS/ (4) //INV &mdash; GOOD problem!!!!↵

http://www.spoj.com/problems/KSMALL/ (5) //fast sort /or/ quick-select↵

http://www.spoj.com/problems/RKS/ (3) //use map↵

http://www.spoj.com/problems/SPCJ/ (4) //reverse + go from back↵

http://codeforces.com/contest/785/problem/B (2) //last-first + vice versa↵

http://codeforces.com/contest/798/problem/D (4) //Take 1st then take best B of every pair (sort by A)↵

http://codeforces.com/contest/810/problem/B (2)↵

http://codeforces.com/contest/810/problem/C (3) //+Math↵

http://codeforces.com/contest/814/problem/A (1) //Pro prváky &mdash; but nice observation↵

http://codeforces.com/contest/817/problem/B (3) //Frequency of TOP 3↵

10769 UVA (3) //Sadly N^4 passes↵

13208 UVA (4) //Sort + Prefix Sum↵

13212 UVA (3) //Number of inversions↵

http://codeforces.com/contest/831/problem/C (3) //NICE ~ Check all "add" against first↵

http://codeforces.com/contest/831/problem/D (4) //Can be solved with BS+Max-Match↵

http://codeforces.com/contest/841/problem/C (3) //NICE &mdash; match greatest to lowest↵

http://codeforces.com/contest/845/problem/C (2) //EASY &mdash; pro prvaky↵

http://www.spoj.com/problems/HSHW/ (4) //Test every big/low pair + big/big low/low on +/-↵

http://www.spoj.com/problems/CODESPTB/ (3) //Count inversions [BASIC]↵

http://codeforces.com/contest/863/problem/B (2) //Sort and omit 2↵

http://www.spoj.com/problems/AMR10G/ (2) //Easy yet NICE↵

http://codeforces.com/contest/12/problem/C (2) //Very simple↵

http://codeforces.com/contest/16/problem/B (1) //[EASY]↵

http://codeforces.com/contest/22/problem/D (3) //Sort by begin + sweep↵

http://codeforces.com/contest/23/problem/C (3) //Take them by pairs + add last↵

http://codeforces.com/contest/24/problem/B (3) //Simple follow the rules↵

http://codeforces.com/contest/27/problem/B (3) //Compare number of victories↵

http://codeforces.com/contest/27/problem/C (4) //[NICE] Find next bigger/lesser (sort)↵

</spoiler>↵

<spoiler summary="spanning_tree">↵

http://codeforces.com/contest/76/problem/A (4) //[VERY NICE] Sort by A and KEEP spanning + one edge↵

LA 6622 &mdash; Absurdistan Roads (4) //Plus one edge↵

UVA 12176↵

UVA 10600↵

UVA 10724↵

https://www.hackerrank.com/contests/june-world-codesprint/challenges/johnland↵

UVA 11710↵

Gym 101252C [2014-2015 CT S02E05: Codeforces Trainings Season 2 Episode 5 &mdash; 2009-2010 ACM-ICPC]↵

Gym 101047I [2015 USP Try-outs][HARD]↵

UVA 11183 [Directed]↵

LightOJ 1101↵

https://www.codechef.com/problems/CHEFELEC↵

UVA 10307↵

http://codeforces.com/problemset/problem/598/D↵

http://codeforces.com/problemset/problem/32/C↵

http://codeforces.com/problemset/problem/744/A↵

https://devskill.com/CodingProblems/ViewProblem/344↵

908 &mdash; Re-connecting Computer Sites [UVA]↵

1208 &mdash; Oreon [UVA]↵

1235 &mdash; Anti Brute Force Lock [UVA]↵

10034 &mdash; Freckles [UVA]↵

11228 &mdash; Transportation system [UVA]↵

11733 &mdash; Airports [UVA]↵

11747 &mdash; Heavy Cycle Edges [UVA]↵

BLINNET SPOJ (3)↵

11183 UVA (4) //Directed [need to know algo!]↵

http://www.spoj.com/problems/ULM09/ (3) //Sum-Kruskal↵

http://www.spoj.com/problems/IITKWPCG/ (4) //VERY NICE [log instead of price]↵

http://codeforces.com/contest/17/problem/B (3) //Spanning tree [no dsu]↵

</spoiler>↵

<spoiler summary="spfa">↵

LightOJ 1074↵

UVA 1171↵

UVA 11478↵

UVA 12768↵

11478 UVA (5)↵

</spoiler>↵

<spoiler summary="sqrt">↵

12003 UVA 7↵

11990 UVA (5)↵

http://www.spoj.com/problems/GIVEAWAY/ (7) //SQRT + BS >  [or Seg+Trie]↵

http://codeforces.com/contest/786/problem/C (5) //Nsqrn (bg) + sqrSegs (end)↵

http://codeforces.com/contest/840/problem/D (5) //NICE &mdash; Either frequent OR brute-force↵

http://codeforces.com/contest/13/problem/E //VERY NICE [SQRT-BLOCK UPDATE/JUMP]↵

http://codeforces.com/contest/85/problem/D (4) //NICE [ST shall work too]↵

</spoiler>↵

<spoiler summary="stl">↵

http://codeforces.com/contest/81/problem/A (2) //Stack OR string↵

http://codeforces.com/contest/78/problem/A (1) //fgets + imple↵

http://codeforces.com/contest/69/problem/E (3) //NICE [2POINTERS][SET][MAP]↵

http://www.spoj.com/problems/RMID/ //Dynamic Median↵

http://www.spoj.com/problems/RMID2/ //Dynamic Median↵

http://codeforces.com/problemset/problem/713/C //Dynamic Median↵

http://www.spoj.com/problems/EC_ESTA/ //Dynamic median↵

http://codeforces.com/contest/799/problem/B (2) //EASY &mdash; MAP↵

http://codeforces.com/contest/808/problem/D (3) //MAP↵

10887 (2) //string + map↵

10730 (3) //Easy with hash-map↵

http://codeforces.com/contest/821/problem/C (3) //STACK (vector) Nice+Easy↵

http://www.spoj.com/problems/SOLVEIT/ (3) //Set + lower_bound↵

http://www.spoj.com/problems/IITKWPCA/ (2) //Set + getline↵

http://codeforces.com/contest/849/problem/D (5) //Queue↵

http://www.spoj.com/problems/CRAN02/ (4) //Map (+Math)↵

http://www.spoj.com/problems/MAX_NUM/ (4) //Queue (possibly multiple ways)↵

http://www.spoj.com/problems/SID/ (5) //Sort + Vector (or similar) [strict TLE]↵

http://www.spoj.com/problems/RPLD/ (2) //Map of sets↵

http://codeforces.com/contest/861/problem/D (4) //unordered map of sets↵

http://www.spoj.com/problems/FACEFRND/ (2) //Set or Bitset↵

http://www.spoj.com/problems/HACKRNDM/ (3) //Easy &mdash; map↵

http://codeforces.com/contest/847/problem/K (4) //NICE Map+Queue↵

http://codeforces.com/contest/855/problem/A (1) //set↵

http://codeforces.com/contest/4/problem/C (2) //map+string↵

http://codeforces.com/contest/5/problem/E (6) //iffs + RMQ+BS+SET [or other sol]↵

http://codeforces.com/contest/44/problem/A (1) //Set + pair↵

http://codeforces.com/contest/45/problem/C (4) //NICE &mdash; Handling with sets↵

</spoiler>↵

<spoiler summary="strings">↵

http://codeforces.com/contest/43/problem/B (2) //Frequency↵

http://codeforces.com/contest/50/problem/B (2) //Frequency + Power↵

http://www.spoj.com/problems/MINMOVE/ (3) //Minimal lexicographical rotation↵

http://www.spoj.com/problems/BWHEELER/ //Burrows Wheeler↵

http://www.spoj.com/problems/EDIST/ //Edit Distance↵

3189 LA //Edit Distance↵

https://www.hackerrank.com/contests/morgan-stanley-2015/challenges/minimum-transformation-cost/problem //Edit Distance↵

http://codeforces.com/gym/101492/problem/L //Laevenstein Distance↵

UVA 13068 //Lexicographically lowest rotation↵

2755 [LA]//Lexicographically lowest rotation↵

LightOJ 1073 //Lexicographically Shortest Superstring↵

http://codeforces.com/contest/762/problem/C 5↵

http://www.spoj.com/problems/LCS0/ 10 //LCS↵

http://www.spoj.com/problems/IITWPC4H/ 2 //Frequence array↵

13186 UVA (6)  //Bitset + Trie ~ NICE [6-7 mby?]↵

http://codeforces.com/contest/798/problem/B (2) //Brute-force .. pro prváky↵

10745 UVA (4) //Frequency (N^2 possible if efficient!!)↵

http://codeforces.com/contest/822/problem/B (2) //Easy pro prvaky (slightly imple.)↵

http://codeforces.com/contest/828/problem/C (4) //+Sorting (process only necessary!)↵

http://codeforces.com/contest/832/problem/B (3) //Naive compare back+front [+freq]↵

http://www.spoj.com/problems/STC04/ (5) //Next + pairs O(N*26) [frist look O(26^2*N)]↵

http://www.spoj.com/problems/IITKWPCJ/ (4) //GCD or HASHING↵

http://www.spoj.com/problems/SUBSN/ (4) //Next (NICE &mdash; bad input): ↵

http://www.spoj.com/problems/BOGGLE/ (2) //EASY [MAP][STREAM]↵

http://www.spoj.com/problems/MAIN8_E/ (4) //VERY NICE &mdash; Next function↵

http://www.spoj.com/problems/STRMATCH/ (3) //Nice matching, yet low constraints on "N"↵

http://www.spoj.com/problems/FINDSR/ (3) //Clever bruteforce works here (NlogN)↵

http://codeforces.com/contest/39/problem/J (2) //Simple iteration over string↵

http://codeforces.com/contest/876/problem/E (4) //Compare from back + make fail-pairs↵

</spoiler>↵

<spoiler summary="suffix_array">↵

UVA 760 //LCS↵

UVA 1227 //LCS↵

http://www.spoj.com/problems/LCS/en/  //LCS↵

UVA 11512↵

7502 [LA]↵

Gym 100923D [2015 ACM National Contest Romania &mdash; Round 1]↵

UVA 1254↵

UVA 12191↵

UVA 12206↵

https://www.codechef.com/problems/INSQ16F↵

3943 LA↵

UVA 11107↵

UVA 12974↵

UVA 10526↵

Davos and Reading [INSOMNIA] //Awesome problem but can't find link [hard] &mdash; non of regular judges↵

UVA 12338↵

https://devskill.com/CodingProblems/ViewProblem/328↵

12191 UVA 5↵

SARRAY SPOJ 3↵

4513 LA 6↵

http://www.spoj.com/problems/LCS2/ 7 // must be linear (SA+LCP+MQ)↵

http://codeforces.com/contest/802/problem/I 7 //NICE! SA+LCP+(Segmentree/queue)↵

http://www.spoj.com/problems/LONGCS/ //5 LCS  of multiple strings (NICE)↵

http://www.spoj.com/problems/SUBLEX/ //5 VERY NICE: Kth substring↵

http://codeforces.com/contest/873/problem/F //6 VERY NICE: SA+Histogram↵

http://codeforces.com/contest/30/problem/E //7 VERY NICE: [many other sols: Manach/KMP/HASH...]↵

6856 &mdash; Circle of digits //7 [VERY NICE]↵

</spoiler>↵

<spoiler summary="ternary_search">↵

LightOJ 1146↵

Gym 101482G [2014-2015 Northwestern European Regional Contest (NWERC 2014)]↵

Gym 101309D [2010-2011 ACM-ICPC Northeastern European Regional Contest (NEERC 10)]↵

UVA 13010 //+Dijkstra↵

2015-2016 CTU Open Contest: Chasing the Cheetah↵

12197 UVA (4)↵

http://www.spoj.com/problems/KOPC12A/ (4) //TS (sadly brute-force works too N^2)↵

</spoiler>↵

<spoiler summary="topo">↵

UVA 11686↵

LightOJ 1034↵

UVA 10305↵

124 &mdash; Following Orders [UVA]↵

200 &mdash; Rare Order [UVA]↵

872 &mdash; Ordering [UVA]↵

11060 &mdash; Beverages [UVA]↵

http://codeforces.com/contest/765/problem/E 5↵

http://codeforces.com/contest/770/problem/C 4 //reduce + toposort↵

http://codeforces.com/contest/825/problem/E 4 //Toposort from biggest/backward↵

http://www.spoj.com/problems/CODESPTI/ (6) //VERY NICE &mdash; Hard/Weak children↵

</spoiler>↵

<spoiler summary="treap">
http://codeforces.com/contest/47/problem/B (2) //[EASY][Toposort on 3 elements]↵

</spoiler>↵

<spoiler summary="treap">↵

http://codeforces.com/contest/879/problem/E (6) //[VERY NICE][Making somponents]

http://codeforces.com/contest/762/problem/E 6↵

http://www.spoj.com/problems/COUNT1IT/ 5↵

http://www.spoj.com/problems/IITWPC4D/ 4 //From end &mdash; pick i-th + del i-th↵

http://www.spoj.com/problems/ALLIN1/ 4 //Typical treap operations↵

http://codeforces.com/contest/847/problem/D 5 //Prolly overkill &mdash; VERY NICE↵

http://codeforces.com/contest/863/problem/D 4 //Not desired solution↵

http://www.spoj.com/problems/KOILINE/ (4) //VERY NICE &mdash; Iterate from back &mdash; get+remove↵

http://www.spoj.com/problems/TWIST/ (5) //NICE: Reverse ↵

http://www.spoj.com/problems/MEANARR/ (5) //VERY NICE! [POLICY][SHORT]↵

</spoiler>↵

<spoiler summary="tree">↵

http://codeforces.com/contest/746/problem/G 5↵

http://codeforces.com/contest/750/problem/F 9↵

http://www.spoj.com/problems/RTREE/ 3 //longest path tree &mdash; query↵

13175 UVA (2) //something like preorder build↵

http://codeforces.com/contest/796/problem/C (3) //Just counting &mdash; inc by at most 2↵

http://codeforces.com/contest/797/problem/D (4) //VERY NICE &mdash; sort + D&C all↵

http://codeforces.com/contest/805/problem/E (4) //NICE &mdash; Treewidth coloring (greedy)↵

http://codeforces.com/contest/828/problem/D (3) //Star construction↵

http://www.spoj.com/problems/TREEDEGREE/ (3) //Degree from euler tree↵

http://www.spoj.com/problems/UCV2013J/ (3) //Find what is leaf in Binary Tree↵

http://www.spoj.com/problems/GCPC11J/ (3) //Finding ceter↵

http://codeforces.com/contest/34/problem/D (3) //Simple reconstruction + DFS↵

</spoiler>↵

<spoiler summary="tree-dp">↵

http://www.spoj.com/problems/PT07X/ (4) //Classical- VC on tree [NICE]↵

http://codeforces.com/contest/81/problem/E (6) //[NICE][PSEUDOFOREST REDUCTION]↵

http://codeforces.com/contest/61/problem/D (4) //dfs-only might works too ↵

LA 6631 &mdash; Jingle Balls (4) //[NICE][SIMPLE]↵

https://www.codechef.com/problems/TRANDED //By [user:sahil070197,2017-11-09]↵

13089 &mdash; Golden Coins (UVA)↵

http://codeforces.com/problemset/problem/855/C↵

http://codeforces.com/problemset/problem/718/D↵

https://www.codechef.com/problems/TWOCOINS↵

7649 &mdash; Performance Review (LA)↵

http://codeforces.com/problemset/problem/741/D↵

http://codeforces.com/problemset/problem/592/D↵

https://www.codechef.com/problems/TOMJERGA↵

http://codeforces.com/problemset/problem/814/D↵

1220 &mdash; Party at Hali-Bula (UVA)↵

https://www.hackerrank.com/contests/june-world-codesprint/challenges/r-tree-decoration/problem↵

12452 &mdash; Plants vs. Zombies HD SP (UVA)↵

http://codeforces.com/problemset/problem/735/E↵

https://www.codechef.com/problems/COLTREE↵

12466 &mdash; Ancestors (UVA)↵

6829 &mdash; Intrepid climber (LA)↵

https://www.hackerrank.com/contests/101hack35/challenges/jeanies-route↵

12257 &mdash; The Queue (UVA)↵

http://codeforces.com/problemset/problem/805/F↵

http://codeforces.com/problemset/problem/763/D↵

1218 &mdash; Perfect Service↵

3346 &mdash; Perfect Domination on Trees (same as above -_-)↵

12093 &mdash; Protecting Zonk↵

10859 &mdash; Placing Lampposts↵

http://codeforces.com/problemset/problem/23/E //NICE [but requires big int]↵

http://codeforces.com/problemset/problem/14/D (5) //NICE [sorting-one][2DFS]↵

http://www.spoj.com/problems/TWOPATHS/ (6) //VERY NICE Same as above ~ bigger constraints↵

http://codeforces.com/contest/868/problem/E (8) //VERY NICE &mdash; HARD &mdash; on tree↵

</spoiler>↵

<spoiler summary="trie_bit">↵

http://codeforces.com/problemset/problem/706/D↵

https://www.hackerrank.com/contests/w8/challenges/black-box-1↵

http://codeforces.com/contest/714/problem/C 5↵

http://www.spoj.com/problems/SUBXOR/ (4)↵

http://codeforces.com/contest/817/problem/E (5) //Classical &mdash; remember sum! NICE!↵

http://codeforces.com/contest/37/problem/C (4) //NICE &mdash; Prefix dictionary [or math]↵

</spoiler>↵

<spoiler summary="trie_string">↵

2642 [LA]↵

UVA 10860↵

UVA 10295↵

UVA 13186 //+Bitset↵

UVA 1123↵

UVA 12506↵

UVA 11539↵

UVA 1142↵

UVA 12359↵

UVA 10282↵

11732 UVA (5)↵

11539 UVA (5)↵

11488 UVA (4)↵

http://www.spoj.com/problems/TRYCOMP/ (4)↵

10860 UVA (4) //DP + Trie [nice &mdash; slightly generic]↵

http://www.spoj.com/problems/DICT/ (4) //Sample trie &mdash; but slightly weak/wrong data-set↵

</spoiler>↵

<spoiler summary="TSP">↵

Gym 100818E [2015-2016 ACM-ICPC Southeastern European Regional Programming Contest (SEERC 2015)]↵

3725 [LA]↵

UVA 10496↵

Gym 101020H [2015 Syrian Private Universities Collegiate Programming Contest] N!↵

LightOJ 1057↵

UVA 11643 //[NICE][BFS]↵

3305 [LA] //On plane↵

10937 UVA (4) //find '!' / BFS / TSP &mdash; NICE!↵

10944 UVA (4) ↵

10818 UVA (5) //Easy &mdash; but not-easy implementation: ++Dijkstra [LEX!]↵

http://www.spoj.com/problems/A_W_S_N/ (4) //BFS + TSP (path) &mdash; NICE↵

</spoiler>↵

<spoiler summary="two-pointers">↵

http://codeforces.com/contest/84/problem/B (2) //EASY //ll↵

http://codeforces.com/contest/79/problem/C (4) //NICE &mdash; [STRINGS][SET][COMPARE]↵

http://codeforces.com/contest/746/problem/F 6↵

11436 UVA (5)↵

http://codeforces.com/contest/760/problem/D 4↵

11386 UVA (4)↵

http://www.spoj.com/problems/WOWSUBSTR2/ 3↵

http://www.spoj.com/problems/ARRAYSUB/ 4↵

http://www.spoj.com/problems/CODFURY/ 3 //easy &mdash; ukazkove↵

http://codeforces.com/contest/769/problem/B 3 //sort + TP↵

http://codeforces.com/contest/814/problem/C 4 //NICE &mdash; maybe some DP +/-↵

http://www.spoj.com/problems/CRAN04/ 4 //NICE &mdash; (more or less) 3 pointers↵

http://www.spoj.com/problems/OPCPIZZA/ 3 //NICE [EASY] [AGAINS EACH OTHER]↵

http://www.spoj.com/problems/ALIEN/ (3) //Classical↵

http://www.spoj.com/problems/HOTELS/ (3) //Classical & Easy↵

http://www.spoj.com/problems/KOIREP/ (4) //VERY NICE &mdash; N buckedt find mid diff↵

http://codeforces.com/contest/6/problem/E (4) //NICE &mdash; Multiset↵

http://codeforces.com/contest/873/problem/C (3) //NICE &mdash; M times 2P tenchique↵

</spoiler>↵

<spoiler summary="wavelet_tree">↵

UVA 1480↵

http://www.spoj.com/problems/ILKQUERY/↵

http://codeforces.com/contest/840/problem/D //Proposed by [user:GreenGrape,2017-10-29]↵

</spoiler>↵

<spoiler summary="
z-Zfunction">↵

http
s://www.spojcodechef.com/problems/SUFEQPRE/ 4↵

</spoiler>↵

<spoiler summary="Zfunction">
CHSTR //Proposed by [user:Apptica,2017-10-27]

http://www.spoj.com/problems/SUFEQPRE/↵

http://codeforces.com/problemset/problem/126/B↵

</spoiler>↵

<spoiler summary="2SAT">↵

11930 UVA (4)↵

http://codeforces.com/contest/776/problem/D (5) ↵

</spoiler>↵

Finally if you would like to add some problem to the list &mdash; even though I would be glad, please do so only in case of:↵

1. It is very interesting↵

2. There is nothing, or low number of problems in the topic↵

3. You add it in "bigger amount" at once↵

Thank you.↵

Offcourse if you have any remarks, questionns or requests, don't hesitate to ask.↵

PS: I'm sorry but there might be some duplicities. In that case, either report it or ignore it (unless they are in different topics, then it have reason :) )↵

Good Luck & Have Nice Day↵

#### History

Revisions

Rev. Lang. By When Δ Comment
en9 -Morass- 2019-08-16 18:25:45 25205 Next update (but prolly fails :/)
en8 -Morass- 2018-09-03 15:50:40 101 bridge update
en7 -Morass- 2018-09-03 15:48:08 6797 Josephus n Fenwick update
en6 -Morass- 2018-06-29 11:21:42 0 (published)
en5 -Morass- 2018-01-23 17:23:19 2680 Added proposed SCC problem
en4 -Morass- 2018-01-01 02:47:24 15110 New problems (for December) added [monthly update]
en3 -Morass- 2017-12-01 02:58:50 5798 New problems (for November) added [monthly update]
en2 -Morass- 2017-11-09 04:09:11 11651 Added a few problems
en1 -Morass- 2017-10-19 02:33:13 109672 Initial revision (published)