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Before contest
Codeforces Round #851 (Div. 2)
37:45:50
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Difficulty:
—
combinatorics
combine-tags-by-or
*combine tags by OR
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
1787D
Game on Axis
combinatorics
,
dfs and similar
,
dsu
,
graphs
,
implementation
1900
x2259
1784E
Infinite Game
brute force
,
combinatorics
,
dp
,
games
,
probabilities
x111
1784D
Wooden Spoon
combinatorics
,
dp
x497
1781F
Bracket Insertion
combinatorics
,
dp
,
math
,
trees
2700
x500
1780F
Three Chairs
bitmasks
,
brute force
,
combinatorics
,
data structures
,
dp
,
number theory
,
sortings
x806
1778D
Flexible String Revisit
combinatorics
,
dp
,
math
,
probabilities
x1527
1777D
Score of a Tree
bitmasks
,
combinatorics
,
dfs and similar
,
dp
,
math
,
probabilities
,
trees
x1984
1777B
Emordnilap
combinatorics
,
greedy
,
math
x12876
1774G
Segment Covering
brute force
,
combinatorics
,
constructive algorithms
,
data structures
,
dp
,
trees
3200
x177
1773G
Game of Questions
bitmasks
,
combinatorics
,
dp
,
fft
,
math
,
probabilities
2800
x182
1773D
Dominoes
combinatorics
,
flows
,
graph matchings
,
greedy
2600
x256
1771A
Hossam and Combinatorics
combinatorics
,
math
,
sortings
900
x17325
1770F
Koxia and Sequence
bitmasks
,
combinatorics
,
dp
,
math
,
number theory
3100
x334
1770E
Koxia and Tree
combinatorics
,
dfs and similar
,
dp
,
dsu
,
math
,
probabilities
,
trees
2400
x1035
1768E
Partial Sorting
combinatorics
,
math
,
number theory
2300
x1345
1767D
Playoff
combinatorics
,
constructive algorithms
,
dp
,
greedy
,
math
1500
x7111
1765C
Card Guessing
combinatorics
,
dp
,
probabilities
2600
x199
1764D
Doremy's Pegging Game
combinatorics
,
dp
,
math
2000
x2094
1763D
Valid Bitonic Permutations
combinatorics
,
dp
,
implementation
,
math
,
number theory
2200
x1526
1762E
Tree Sum
combinatorics
,
math
,
trees
2600
x397
1762C
Binary Strings are Fun
combinatorics
,
math
1400
x6807
1761F2
Anti-median (Hard Version)
combinatorics
,
dp
,
math
3500
x40
1761D
Carry Bit
combinatorics
,
math
2100
x1849
1758E
Tick, Tock
combinatorics
,
dfs and similar
,
dsu
,
graphs
2500
x593
1750G
Doping
combinatorics
,
dp
,
math
3300
x103
1750F
Majority
combinatorics
,
dp
,
math
,
strings
2700
x479
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
1747E
List Generation
combinatorics
,
dp
,
math
2900
x372
1743G
Antifibonacci Cut
bitmasks
,
combinatorics
,
constructive algorithms
,
data structures
,
dp
,
hashing
,
math
3000
x179
1743A
Password
brute force
,
combinatorics
,
implementation
,
math
800
x22543
1740F
Conditional Mix
combinatorics
,
dp
,
math
2600
x552
1739C
Card Game
combinatorics
,
constructive algorithms
,
dp
,
games
1500
x7135
1738E
Balance Addicts
combinatorics
,
dp
,
math
,
two pointers
2300
x1204
1737E
Ela Goes Hiking
combinatorics
,
dp
,
math
,
probabilities
2500
x749
1735D
Meta-set
brute force
,
combinatorics
,
data structures
,
hashing
,
math
1700
x4386
1732A
Bestie
brute force
,
combinatorics
,
constructive algorithms
,
implementation
,
math
,
number theory
1000
x11610
1731F
Function Sum
brute force
,
combinatorics
,
dp
,
fft
,
math
2500
x479
1730E
Maximums and Minimums
combinatorics
,
data structures
,
divide and conquer
,
number theory
2700
x452
1729G
Cut Substrings
combinatorics
,
dp
,
hashing
,
strings
,
two pointers
2100
x1669
1728G
Illumination
binary search
,
bitmasks
,
brute force
,
combinatorics
,
dp
,
math
,
two pointers
2700
x302
1726G
A Certain Magical Party
combinatorics
,
data structures
,
greedy
,
sortings
3300
x164
1726E
Almost Perfect
combinatorics
,
fft
,
math
2400
x1145
1725I
Imitating the Key Tree
combinatorics
,
dsu
,
trees
2800
x132
1725E
Electrical Efficiency
combinatorics
,
data structures
,
dp
,
math
,
number theory
,
trees
2500
x259
1725C
Circular Mirror
binary search
,
combinatorics
,
geometry
,
math
,
two pointers
2000
x1092
1717D
Madoka and The Corruption Scheme
combinatorics
,
constructive algorithms
,
greedy
,
math
1900
x3608
1716F
Bags with Balls
combinatorics
,
dp
,
math
,
number theory
2500
x726
1715C
Monoblock
combinatorics
,
data structures
,
implementation
,
math
1700
x7151
1713F
Lost Array
bitmasks
,
combinatorics
,
constructive algorithms
,
dp
,
math
2900
x348
1712E1
LCM Sum (easy version)
binary search
,
brute force
,
combinatorics
,
math
,
number theory
,
two pointers
2300
x1678
1707D
Partial Virtual Trees
combinatorics
,
dfs and similar
,
dp
,
math
,
trees
3000
x418
1705E
Mark and Professor Koro
binary search
,
bitmasks
,
brute force
,
combinatorics
,
data structures
,
greedy
2300
x1660
1705D
Mark and Lightbulbs
combinatorics
,
constructive algorithms
,
greedy
,
math
,
sortings
1800
x5201
1704H2
Game of AI (hard version)
combinatorics
,
fft
,
math
3500
x50
1704H1
Game of AI (easy version)
combinatorics
,
constructive algorithms
,
dp
,
fft
,
math
3200
x131
1701F
Points
combinatorics
,
data structures
,
implementation
,
math
,
matrices
2500
x723
1699C
The Third Problem
combinatorics
,
constructive algorithms
,
math
1700
x8075
1698E
PermutationForces II
brute force
,
combinatorics
,
greedy
,
sortings
,
trees
,
two pointers
2300
x1398
1697E
Coloring
brute force
,
combinatorics
,
constructive algorithms
,
dp
,
geometry
,
graphs
,
greedy
,
implementation
,
math
2400
x990
1696H
Maximum Product?
brute force
,
combinatorics
,
dp
,
greedy
,
implementation
,
math
,
two pointers
3500
x86
1696E
Placing Jinas
combinatorics
,
math
2000
x3172
1691F
K-Set Tree
combinatorics
,
dfs and similar
,
dp
,
math
,
trees
2500
x743
1687E
Become Big For Me
combinatorics
,
constructive algorithms
,
greedy
,
math
,
number theory
3500
x155
1679E
Typical Party in Dorm
bitmasks
,
combinatorics
,
dp
,
strings
2400
x909
1674C
Infinite Replacement
combinatorics
,
implementation
,
strings
1000
x19533
1674B
Dictionary
combinatorics
,
math
800
x22487
1673E
Power or XOR?
bitmasks
,
combinatorics
,
math
,
number theory
2500
x554
1673D
Lost Arithmetic Progression
combinatorics
,
math
,
number theory
1900
x2763
1671F
Permutation Counting
brute force
,
combinatorics
,
dp
,
fft
,
math
2700
x250
1671E
Preorder
combinatorics
,
divide and conquer
,
dp
,
dsu
,
hashing
,
sortings
,
trees
2100
x2270
1670F
Jee, You See?
bitmasks
,
combinatorics
,
dp
2400
x763
1667E
Centroid Probabilities
combinatorics
,
dp
,
fft
,
math
3000
x384
1666F
Fancy Stack
combinatorics
,
dp
,
implementation
2200
x880
1663D
Is it rated - 3
*special problem
,
combinatorics
,
dp
,
math
x1206
1662N
Drone Photo
combinatorics
,
math
,
sortings
x446
1658B
Marin and Anti-coprime Permutation
combinatorics
,
math
,
number theory
800
x17234
1657E
Star MST
combinatorics
,
dp
,
graph matchings
,
math
2200
x1488
1654H
Three Minimums
combinatorics
,
constructive algorithms
,
divide and conquer
,
dp
,
fft
,
math
3500
x54
1651E
Sum of Matchings
brute force
,
combinatorics
,
constructive algorithms
,
dfs and similar
,
graph matchings
,
greedy
,
math
2600
x403
1648C
Tyler and Strings
combinatorics
,
data structures
,
implementation
1900
x2476
1648A
Weird Sum
combinatorics
,
data structures
,
geometry
,
math
,
matrices
,
sortings
1400
x9967
1644F
Basis
combinatorics
,
fft
,
math
,
number theory
2900
x263
1644E
Expand the Path
brute force
,
combinatorics
,
data structures
,
implementation
,
math
1900
x2560
1641E
Special Positions
combinatorics
,
divide and conquer
,
fft
,
math
3300
x168
1641D
Two Arrays
bitmasks
,
brute force
,
combinatorics
,
greedy
,
hashing
,
math
,
two pointers
2700
x817
1630E
Expected Components
combinatorics
,
math
,
number theory
,
probabilities
2900
x322
1628D2
Game on Sum (Hard Version)
combinatorics
,
dp
,
games
,
math
2400
x1523
1628D1
Game on Sum (Easy Version)
combinatorics
,
dp
,
games
,
math
2100
x2408
1626F
A Random Code Problem
combinatorics
,
dp
,
math
,
number theory
,
probabilities
2800
x530
1622D
Shuffle
combinatorics
,
math
,
two pointers
2000
x3242
1620G
Subsequences Galore
bitmasks
,
combinatorics
,
dp
2400
x727
1616H
Keep XOR Low
bitmasks
,
combinatorics
,
data structures
,
divide and conquer
,
dp
,
math
3000
x490
1615F
LEGOndary Grandmaster
combinatorics
,
dp
,
math
2800
x520
1614C
Divan and bitwise operations
bitmasks
,
combinatorics
,
constructive algorithms
,
dp
,
math
1500
x8662
1613F
Tree Coloring
combinatorics
,
divide and conquer
,
fft
2600
x515
1612G
Max Sum Array
combinatorics
,
constructive algorithms
,
greedy
,
sortings
2500
x673
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