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Before contest
Codeforces Round #851 (Div. 2)
36:56:14
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graphs
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
1792F2
Graph Coloring (hard version)
brute force
,
combinatorics
,
divide and conquer
,
dp
,
fft
,
graphs
2900
x197
1792F1
Graph Coloring (easy version)
combinatorics
,
dp
,
graphs
2700
x330
1790G
Tokens on Graph
constructive algorithms
,
dfs and similar
,
graphs
,
shortest paths
2300
x588
1790F
Timofey and Black-White Tree
brute force
,
dfs and similar
,
divide and conquer
,
graphs
,
greedy
,
math
,
shortest paths
,
trees
2100
x1815
1787D
Game on Axis
combinatorics
,
dfs and similar
,
dsu
,
graphs
,
implementation
1900
x2259
1783F
Double Sort II
dfs and similar
,
flows
,
graph matchings
,
graphs
2500
x583
1779G
The Game of the Century
constructive algorithms
,
graphs
,
shortest paths
3000
x209
1779E
Anya's Simultaneous Exhibition
constructive algorithms
,
graphs
,
greedy
,
interactive
,
sortings
2400
x1352
1778F
Maximizing Root
dfs and similar
,
dp
,
graphs
,
math
,
number theory
,
trees
x288
1777E
Edge Reverse
binary search
,
dfs and similar
,
graphs
,
trees
x989
1775D
Friendly Spiders
dfs and similar
,
graphs
,
math
,
number theory
,
shortest paths
1800
x3708
1772F
Copy of a Copy of a Copy
constructive algorithms
,
dfs and similar
,
graphs
,
implementation
,
sortings
2000
x1470
1770D
Koxia and Game
constructive algorithms
,
data structures
,
dfs and similar
,
dsu
,
flows
,
games
,
graph matchings
,
graphs
,
implementation
2000
x2921
1768D
Lucky Permutation
constructive algorithms
,
dfs and similar
,
graphs
,
greedy
1800
x4903
1767E
Algebra Flash
bitmasks
,
brute force
,
dp
,
graphs
,
math
,
meet-in-the-middle
,
trees
2500
x542
1765H
Hospital Queue
binary search
,
graphs
,
greedy
,
implementation
2200
x799
1764C
Doremy's City Construction
graphs
,
greedy
1400
x6856
1763F
Edge Queries
data structures
,
dfs and similar
,
dp
,
dsu
,
graphs
,
trees
3000
x233
1763E
Node Pairs
dp
,
graphs
,
math
,
number theory
2200
x1237
1761E
Make It Connected
binary search
,
brute force
,
constructive algorithms
,
dsu
,
graphs
,
greedy
,
matrices
,
trees
,
two pointers
2400
x1336
1761C
Set Construction
constructive algorithms
,
dfs and similar
,
graphs
,
greedy
1400
x6909
1760G
SlavicG's Favorite Problem
bitmasks
,
dfs and similar
,
graphs
1700
x4733
1758E
Tick, Tock
combinatorics
,
dfs and similar
,
dsu
,
graphs
2500
x593
1753D
The Beach
constructive algorithms
,
dfs and similar
,
graphs
,
shortest paths
2400
x1201
1749E
Cactus Wall
constructive algorithms
,
dfs and similar
,
graphs
,
shortest paths
2400
x1224
1741G
Kirill and Company
bitmasks
,
brute force
,
dfs and similar
,
dp
,
flows
,
graphs
,
shortest paths
2200
x1072
1741D
Masha and a Beautiful Tree
dfs and similar
,
divide and conquer
,
graphs
,
sortings
,
trees
1300
x10827
1740I
Arranging Crystal Balls
data structures
,
divide and conquer
,
divide and conquer
,
dp
,
geometry
,
graphs
,
number theory
3500
x53
1739D
Reset K Edges
binary search
,
data structures
,
dfs and similar
,
graphs
,
greedy
,
trees
1900
x3789
1738F
Connectivity Addicts
constructive algorithms
,
dsu
,
graphs
,
greedy
,
interactive
,
shortest paths
,
trees
2400
x960
1738D
Permutation Addicts
constructive algorithms
,
data structures
,
dfs and similar
,
dsu
,
graphs
,
trees
1900
x2808
1737D
Ela and the Wiring Wizard
brute force
,
dp
,
graphs
,
greedy
,
implementation
,
shortest paths
2200
x1597
1735C
Phase Shift
dfs and similar
,
dsu
,
graphs
,
greedy
,
implementation
,
strings
1400
x7885
1726D
Edge Split
brute force
,
constructive algorithms
,
dfs and similar
,
dsu
,
graphs
,
probabilities
,
trees
2000
x2994
1726C
Jatayu's Balanced Bracket Sequence
data structures
,
dsu
,
graphs
,
greedy
1300
x10270
1725M
Moving Both Hands
dp
,
graphs
,
shortest paths
1800
x1870
1721F
Matching Reduction
brute force
,
constructive algorithms
,
dfs and similar
,
flows
,
graph matchings
,
graphs
,
interactive
2800
x275
1718E
Impressionism
constructive algorithms
,
graphs
,
implementation
,
math
3500
x74
1717F
Madoka and The First Session
constructive algorithms
,
flows
,
graph matchings
,
graphs
,
implementation
2500
x406
1715E
Long Way Home
data structures
,
divide and conquer
,
dp
,
geometry
,
graphs
,
greedy
,
shortest paths
2400
x1203
1715D
2+ doors
2-sat
,
bitmasks
,
graphs
,
greedy
1900
x3979
1711B
Party
brute force
,
graphs
1300
x11609
1709F
Multiset of Strings
bitmasks
,
brute force
,
dp
,
fft
,
flows
,
graphs
,
math
,
meet-in-the-middle
,
trees
2500
x447
1707C
DFS Trees
dfs and similar
,
dsu
,
graphs
,
greedy
,
sortings
,
trees
2400
x1107
1704E
Count Seconds
brute force
,
constructive algorithms
,
dp
,
graphs
,
implementation
,
math
2200
x1932
1702E
Split Into Two Sets
dfs and similar
,
dsu
,
graphs
1600
x9250
1698F
Equal Reversal
constructive algorithms
,
graphs
,
implementation
,
math
2800
x432
1697F
Too Many Constraints
2-sat
,
constructive algorithms
,
graphs
,
implementation
2800
x348
1697E
Coloring
brute force
,
combinatorics
,
constructive algorithms
,
dp
,
geometry
,
graphs
,
greedy
,
implementation
,
math
2400
x990
1696F
Tree Recovery
brute force
,
constructive algorithms
,
dfs and similar
,
dsu
,
graphs
,
trees
2600
x724
1695E
Ambiguous Dominoes
constructive algorithms
,
dfs and similar
,
graphs
2700
x355
1695C
Zero Path
brute force
,
data structures
,
dp
,
graphs
,
greedy
,
shortest paths
1700
x8456
1693C
Keshi in Search of AmShZ
graphs
,
greedy
,
shortest paths
2300
x1887
1691E
Number of Groups
data structures
,
dfs and similar
,
dsu
,
graphs
,
greedy
,
sortings
2300
x1466
1690F
Shifting String
graphs
,
math
,
number theory
,
strings
1700
x5539
1689E
ANDfinity
bitmasks
,
brute force
,
constructive algorithms
,
dfs and similar
,
dsu
,
graphs
2500
x966
1687B
Railway System
constructive algorithms
,
graphs
,
greedy
,
interactive
,
sortings
1700
x2917
1682F
MCMF?
data structures
,
flows
,
graphs
,
greedy
,
sortings
,
two pointers
2700
x224
1682E
Unordered Swaps
constructive algorithms
,
dfs and similar
,
graphs
,
greedy
,
math
,
sortings
,
trees
2700
x442
1680F
Lenient Vertex Cover
dfs and similar
,
divide and conquer
,
dsu
,
graphs
,
trees
2600
x391
1679D
Toss a Coin to Your Graph...
binary search
,
dfs and similar
,
dp
,
graphs
1900
x3618
1677C
Tokitsukaze and Two Colorful Tapes
constructive algorithms
,
dfs and similar
,
graphs
,
greedy
1900
x2766
1676G
White-Black Balanced Subtrees
dfs and similar
,
dp
,
graphs
,
trees
1300
x10463
1675D
Vertical Paths
graphs
,
implementation
,
trees
1300
x10320
1674G
Remove Directed Edges
dfs and similar
,
dp
,
graphs
2000
x1948
1672G
Cross Xor
constructive algorithms
,
graphs
,
math
,
matrices
3200
x220
1672F2
Checker for Array Shuffling
constructive algorithms
,
dfs and similar
,
graphs
2800
x635
1672F1
Array Shuffling
constructive algorithms
,
graphs
,
greedy
2000
x2558
1670C
Where is the Pizza?
data structures
,
dfs and similar
,
dsu
,
graphs
,
implementation
,
math
1400
x7929
1666L
Labyrinth
dfs and similar
,
graphs
1800
x2466
1662O
Circular Maze
brute force
,
dfs and similar
,
graphs
,
implementation
x915
1662J
Training Camp
flows
,
graphs
x51
1662F
Antennas
data structures
,
dfs and similar
,
graphs
,
graphs
,
implementation
,
implementation
,
shortest paths
,
shortest paths
x677
1662C
European Trip
dp
,
graphs
,
math
,
matrices
x214
1661B
Getting Zero
bitmasks
,
brute force
,
dfs and similar
,
dp
,
graphs
,
greedy
,
shortest paths
1300
x14010
1659F
Tree and Permutation Game
dfs and similar
,
games
,
graphs
,
trees
3000
x141
1659E
AND-MEX Walk
bitmasks
,
brute force
,
constructive algorithms
,
dfs and similar
,
dsu
,
graphs
2200
x1175
1657F
Words on Tree
2-sat
,
dfs and similar
,
dsu
,
graphs
,
trees
2600
x424
1656I
Neighbour Ordering
constructive algorithms
,
graphs
3500
x61
1656G
Cycle Palindrome
constructive algorithms
,
graphs
,
math
3200
x215
1656F
Parametric MST
binary search
,
constructive algorithms
,
graphs
,
greedy
,
math
,
sortings
2600
x801
1654G
Snowy Mountain
data structures
,
dfs and similar
,
graphs
,
greedy
,
shortest paths
,
trees
2900
x277
1654E
Arithmetic Operations
brute force
,
data structures
,
graphs
,
math
2300
x1665
1651D
Nearest Excluded Points
binary search
,
data structures
,
dfs and similar
,
graphs
,
shortest paths
1900
x4098
1650G
Counting Shortcuts
data structures
,
dfs and similar
,
dp
,
graphs
,
shortest paths
2100
x1971
1648F
Two Avenues
data structures
,
dfs and similar
,
graphs
3500
x49
1648E
Air Reform
data structures
,
dfs and similar
,
divide and conquer
,
dsu
,
graphs
,
implementation
,
trees
3200
x274
1647B
Madoka and the Elegant Gift
brute force
,
constructive algorithms
,
graphs
,
implementation
1200
x13797
1639K
Treasure Hunt
graphs
,
interactive
1639J
Treasure Hunt
graphs
,
interactive
1639I
Treasure Hunt
graphs
,
interactive
1639H
Treasure Hunt
graphs
,
interactive
1639G
Treasure Hunt
graphs
,
interactive
1639F
Treasure Hunt
graphs
,
interactive
1639E
Treasure Hunt
graphs
,
interactive
1639D
Treasure Hunt
graphs
,
interactive
1639C
Treasure Hunt
graphs
,
interactive
1639B
Treasure Hunt
graphs
,
interactive
1639A
Treasure Hunt
graphs
,
interactive
1638C
Inversion Graph
data structures
,
dsu
,
graphs
,
math
1300
x12857
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