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Before contest
Codeforces Round #851 (Div. 2)
36:57:48
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number theory
combine-tags-by-or
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2-sat
binary search
bitmasks
brute force
chinese remainder theorem
combinatorics
constructive algorithms
data structures
dfs and similar
divide and conquer
dp
dsu
expression parsing
fft
flows
games
geometry
graph matchings
graphs
greedy
hashing
implementation
interactive
math
matrices
meet-in-the-middle
number theory
probabilities
schedules
shortest paths
sortings
string suffix structures
strings
ternary search
trees
two pointers
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Problems
#
Name
1792E
Divisors and Table
brute force
,
dfs and similar
,
dp
,
number theory
2400
x751
1787B
Number Factorization
greedy
,
math
,
number theory
1100
x9751
1783E
Game of the Year
brute force
,
data structures
,
math
,
number theory
2300
x1488
1781D
Many Perfect Squares
brute force
,
math
,
number theory
1800
x3748
1780G
Delicious Dessert
binary search
,
dsu
,
hashing
,
math
,
number theory
,
string suffix structures
x351
1780F
Three Chairs
bitmasks
,
brute force
,
combinatorics
,
data structures
,
dp
,
number theory
,
sortings
x806
1780E
Josuke and Complete Graph
binary search
,
brute force
,
data structures
,
math
,
number theory
x820
1780B
GCD Partition
brute force
,
greedy
,
math
,
number theory
x12031
1778F
Maximizing Root
dfs and similar
,
dp
,
graphs
,
math
,
number theory
,
trees
x288
1777C
Quiz Master
binary search
,
math
,
number theory
,
sortings
,
two pointers
x4936
1775D
Friendly Spiders
dfs and similar
,
graphs
,
math
,
number theory
,
shortest paths
1800
x3708
1771C
Hossam and Trainees
greedy
,
math
,
number theory
1600
x6081
1770F
Koxia and Sequence
bitmasks
,
combinatorics
,
dp
,
math
,
number theory
3100
x334
1770C
Koxia and Number Theory
brute force
,
chinese remainder theorem
,
math
,
number theory
1700
x6807
1768E
Partial Sorting
combinatorics
,
math
,
number theory
2300
x1345
1768A
Greatest Convex
greedy
,
math
,
number theory
800
x23072
1766D
Lucky Chains
math
,
number theory
1600
x5706
1765M
Minimum LCM
math
,
number theory
1000
x7454
1764B
Doremy's Perfect Math Class
math
,
number theory
900
x12277
1763E
Node Pairs
dp
,
graphs
,
math
,
number theory
2200
x1237
1763D
Valid Bitonic Permutations
combinatorics
,
dp
,
implementation
,
math
,
number theory
2200
x1526
1762D
GCD Queries
constructive algorithms
,
interactive
,
number theory
2100
x2470
1762B
Make Array Good
constructive algorithms
,
implementation
,
number theory
,
sortings
1100
x12941
1762A
Divide and Conquer
greedy
,
math
,
number theory
800
x16095
1759F
All Possible Digits
binary search
,
data structures
,
greedy
,
math
,
number theory
1800
x2556
1759D
Make It Round
brute force
,
number theory
1400
x8225
1758C
Almost All Multiples
greedy
,
number theory
1400
x9256
1753B
Factorial Divisibility
math
,
number theory
1600
x9163
1750D
Count GCD
combinatorics
,
math
,
number theory
1800
x4242
1749D
Counting Arrays
combinatorics
,
dp
,
math
,
number theory
1900
x4219
1748D
ConstructOR
bitmasks
,
chinese remainder theorem
,
combinatorics
,
constructive algorithms
,
math
,
number theory
2100
x2186
1744E2
Divisible Numbers (hard version)
brute force
,
math
,
number theory
1900
x3774
1744E1
Divisible Numbers (easy version)
brute force
,
math
,
number theory
1500
x7383
1742D
Coprime
brute force
,
greedy
,
number theory
1100
x15630
1740I
Arranging Crystal Balls
data structures
,
divide and conquer
,
divide and conquer
,
dp
,
geometry
,
graphs
,
number theory
3500
x53
1740A
Factorise N+M
constructive algorithms
,
number theory
800
x16540
1737F
Ela and Prime GCD
constructive algorithms
,
math
,
number theory
3300
x93
1736B
Playing with GCD
math
,
number theory
1200
x12877
1734E
Rectangular Congruence
constructive algorithms
,
number theory
2100
x2289
1732E
Location
data structures
,
dp
,
math
,
number theory
2800
x285
1732D2
Balance (Hard version)
brute force
,
data structures
,
number theory
2400
x1076
1732D1
Balance (Easy version)
brute force
,
data structures
,
implementation
,
number theory
1500
x6226
1732A
Bestie
brute force
,
combinatorics
,
constructive algorithms
,
implementation
,
math
,
number theory
1000
x11610
1731E
Graph Cost
dp
,
greedy
,
math
,
number theory
2000
x1979
1731C
Even Subarrays
bitmasks
,
brute force
,
hashing
,
math
,
number theory
1700
x6901
1730E
Maximums and Minimums
combinatorics
,
data structures
,
divide and conquer
,
number theory
2700
x452
1728E
Red-Black Pepper
brute force
,
data structures
,
greedy
,
math
,
number theory
2300
x1363
1725E
Electrical Efficiency
combinatorics
,
data structures
,
dp
,
math
,
number theory
,
trees
2500
x259
1720A
Burenka Plays with Fractions
math
,
number theory
900
x18701
1718F
Burenka, an Array and Queries
data structures
,
math
,
number theory
3300
x76
1718C
Tonya and Burenka-179
data structures
,
greedy
,
math
,
number theory
2400
x1202
1718B
Fibonacci Strings
greedy
,
implementation
,
math
,
number theory
2000
x2301
1717E
Madoka and The Best University
math
,
number theory
2200
x1954
1717A
Madoka and Strange Thoughts
math
,
number theory
800
x17554
1716F
Bags with Balls
combinatorics
,
dp
,
math
,
number theory
2500
x726
1714E
Add Modulo 10
brute force
,
math
,
number theory
1400
x11674
1713D
Tournament Countdown
constructive algorithms
,
greedy
,
interactive
,
number theory
,
probabilities
1800
x4796
1712E2
LCM Sum (hard version)
brute force
,
data structures
,
math
,
number theory
,
two pointers
2500
x929
1712E1
LCM Sum (easy version)
binary search
,
brute force
,
combinatorics
,
math
,
number theory
,
two pointers
2300
x1678
1712B
Woeful Permutation
constructive algorithms
,
greedy
,
number theory
800
x19883
1707F
Bugaboo
bitmasks
,
constructive algorithms
,
dp
,
number theory
3500
x90
1706D2
Chopping Carrots (Hard Version)
brute force
,
constructive algorithms
,
data structures
,
dp
,
greedy
,
math
,
number theory
,
two pointers
2400
x1384
1706D1
Chopping Carrots (Easy Version)
binary search
,
brute force
,
constructive algorithms
,
greedy
,
number theory
1700
x5677
1702F
Equate Multisets
constructive algorithms
,
data structures
,
greedy
,
math
,
number theory
1700
x6503
1699E
Three Days Grace
data structures
,
dp
,
greedy
,
math
,
number theory
,
two pointers
2600
x857
1698G
Long Binary String
bitmasks
,
math
,
matrices
,
meet-in-the-middle
,
number theory
2900
x232
1690F
Shifting String
graphs
,
math
,
number theory
,
strings
1700
x5539
1687E
Become Big For Me
combinatorics
,
constructive algorithms
,
greedy
,
math
,
number theory
3500
x155
1684G
Euclid Guess
constructive algorithms
,
flows
,
graph matchings
,
math
,
number theory
2800
x456
1679A
AvtoBus
brute force
,
greedy
,
math
,
number theory
900
x17979
1673E
Power or XOR?
bitmasks
,
combinatorics
,
math
,
number theory
2500
x554
1673D
Lost Arithmetic Progression
combinatorics
,
math
,
number theory
1900
x2763
1673C
Palindrome Basis
brute force
,
dp
,
math
,
number theory
1500
x9353
1665D
GCD Guess
bitmasks
,
chinese remainder theorem
,
constructive algorithms
,
games
,
interactive
,
math
,
number theory
2000
x3042
1658E
Gojou and Matrix Game
data structures
,
dp
,
games
,
hashing
,
implementation
,
math
,
number theory
,
sortings
2500
x831
1658B
Marin and Anti-coprime Permutation
combinatorics
,
math
,
number theory
800
x17234
1656H
Equal LCM Subsets
data structures
,
math
,
number theory
3200
x255
1656D
K-good
constructive algorithms
,
math
,
number theory
1900
x5662
1656C
Make Equal With Mod
constructive algorithms
,
math
,
number theory
,
sortings
1200
x15596
1654D
Potion Brewing Class
dfs and similar
,
math
,
number theory
,
trees
2100
x2479
1647D
Madoka and the Best School in Russia
constructive algorithms
,
dp
,
math
,
number theory
1900
x4486
1646E
Power Board
brute force
,
dp
,
math
,
number theory
2200
x1909
1644F
Basis
combinatorics
,
fft
,
math
,
number theory
2900
x263
1635D
Infinite Set
bitmasks
,
dp
,
math
,
matrices
,
number theory
,
strings
1800
x5065
1632D
New Year Concert
binary search
,
data structures
,
greedy
,
math
,
number theory
,
two pointers
2000
x3798
1630F
Making It Bipartite
flows
,
graph matchings
,
graphs
,
number theory
3400
x304
1630E
Expected Components
combinatorics
,
math
,
number theory
,
probabilities
2900
x322
1630D
Flipping Range
constructive algorithms
,
dp
,
greedy
,
number theory
2400
x1247
1629B
GCD Arrays
greedy
,
math
,
number theory
800
x21382
1627D
Not Adding
brute force
,
dp
,
math
,
number theory
1900
x6641
1627C
Not Assigning
constructive algorithms
,
dfs and similar
,
number theory
,
trees
1400
x11950
1626F
A Random Code Problem
combinatorics
,
dp
,
math
,
number theory
,
probabilities
2800
x530
1622F
Quadratic Set
constructive algorithms
,
hashing
,
math
,
number theory
2900
x434
1617E
Christmas Chocolates
dfs and similar
,
dp
,
games
,
graphs
,
implementation
,
math
,
number theory
,
shortest paths
,
trees
2700
x683
1617B
GCD Problem
brute force
,
constructive algorithms
,
math
,
number theory
900
x18815
1614D2
Divan and Kostomuksha (hard version)
dp
,
number theory
2300
x1813
1614D1
Divan and Kostomuksha (easy version)
dp
,
number theory
2100
x3079
1612D
X-Magic Pair
math
,
number theory
1600
x7389
1610D
Not Quite Lee
combinatorics
,
dp
,
math
,
number theory
2000
x2288
1609C
Complex Market Analysis
binary search
,
dp
,
implementation
,
number theory
,
schedules
,
two pointers
1400
x8453
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