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Codeforces Round 987 (Div. 2)
19:41:55
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Difficulty:
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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
1970G2
Min-Fund Prison (Medium)
brute force
,
dfs and similar
,
dp
,
graphs
,
trees
2200
x586
1970G1
Min-Fund Prison (Easy)
dfs and similar
,
trees
1900
x1353
1970F3
Playing Quidditch (Hard)
implementation
2300
x359
1970F2
Playing Quidditch (Medium)
implementation
2300
x346
1970F1
Playing Quidditch (Easy)
implementation
2300
x426
1970E3
Trails (Hard)
dp
,
matrices
2200
x743
1970E2
Trails (Medium)
dp
,
matrices
2000
x1298
1970E1
Trails (Easy)
dp
1800
x2211
1970D3
Arithmancy (Hard)
interactive
3100
x110
1970D2
Arithmancy (Medium)
constructive algorithms
,
interactive
,
probabilities
,
strings
2600
x207
1970D1
Arithmancy (Easy)
brute force
,
constructive algorithms
,
interactive
,
strings
2100
x646
1970C3
Game on Tree (Hard)
dfs and similar
,
dp
,
games
,
trees
1900
x1583
1970C2
Game on Tree (Medium)
dfs and similar
,
dp
,
games
,
trees
1700
x2760
1970C1
Game on Tree (Easy)
games
1400
x3488
1970B3
Exact Neighbours (Hard)
constructive algorithms
2300
x488
1970B2
Exact Neighbours (Medium)
constructive algorithms
2100
x817
1970B1
Exact Neighbours (Easy)
constructive algorithms
1900
x1152
1970A3
Balanced Unshuffle (Hard)
constructive algorithms
,
trees
2400
x464
1970A2
Balanced Unshuffle (Medium)
brute force
,
constructive algorithms
,
trees
2400
x444
1970A1
Balanced Shuffle (Easy)
implementation
,
sortings
1000
x4794
1969F
Card Pairing
dp
,
greedy
,
hashing
,
implementation
3000
x274
1969E
Unique Array
binary search
,
data structures
,
divide and conquer
,
dp
,
greedy
2400
x1380
1969D
Shop Game
data structures
,
greedy
,
math
,
sortings
1900
x4626
1969C
Minimizing the Sum
dp
,
implementation
1700
x8785
1969B
Shifts and Sorting
constructive algorithms
,
greedy
1000
x19101
1969A
Two Friends
constructive algorithms
,
implementation
,
math
800
x19963
1968G2
Division + LCP (hard version)
binary search
,
brute force
,
data structures
,
dp
,
hashing
,
math
,
string suffix structures
,
strings
2200
x1968
1968G1
Division + LCP (easy version)
binary search
,
data structures
,
dp
,
hashing
,
string suffix structures
,
strings
1900
x4292
1968F
Equal XOR Segments
binary search
,
data structures
1800
x5523
1968E
Cells Arrangement
constructive algorithms
1600
x10451
1968D
Permutation Game
brute force
,
dfs and similar
,
games
,
graphs
,
greedy
,
math
1300
x14960
1968C
Assembly via Remainders
constructive algorithms
,
number theory
1000
x25062
1968B
Prefiquence
greedy
,
two pointers
800
x27940
1968A
Maximize?
brute force
,
math
,
number theory
800
x34626
1967F
Next and Prev
brute force
,
data structures
,
implementation
3200
x69
1967E2
Again Counting Arrays (Hard Version)
combinatorics
,
dp
,
math
3500
x103
1967E1
Again Counting Arrays (Easy Version)
combinatorics
,
dp
,
fft
,
math
3100
x216
1967D
Long Way to be Non-decreasing
binary search
,
dfs and similar
,
graphs
,
implementation
,
shortest paths
,
two pointers
2800
x676
1967C
Fenwick Tree
bitmasks
,
brute force
,
combinatorics
,
data structures
,
dp
,
math
,
trees
2300
x1774
1967B2
Reverse Card (Hard Version)
brute force
,
math
,
number theory
2200
x3946
1967B1
Reverse Card (Easy Version)
brute force
,
math
,
number theory
1400
x13327
1967A
Permutation Counting
binary search
,
greedy
,
implementation
,
math
,
sortings
1400
x12518
1966B
Rectangle Filling
constructive algorithms
,
implementation
1100
x15021
1966A
Card Exchange
constructive algorithms
,
games
,
greedy
800
x17911
1965F
Conference
data structures
,
flows
3300
x177
1965E
Connected Cubes
constructive algorithms
,
games
3100
x273
1965D
Missing Subarray Sum
constructive algorithms
2900
x431
1965C
Folding Strip
constructive algorithms
,
greedy
,
strings
2300
x1944
1965B
Missing Subsequence Sum
bitmasks
,
constructive algorithms
,
greedy
,
number theory
1800
x6741
1965A
Everything Nim
games
,
greedy
,
math
,
sortings
1400
x13781
1958J
Necromancer
*special problem
3200
x32
1958I
Equal Trees
*special problem
,
graphs
,
meet-in-the-middle
3100
x34
1958H
Composite Spells
*special problem
,
dp
2600
x78
1958G
Observation Towers
*special problem
2400
x110
1958F
Narrow Paths
*special problem
,
combinatorics
2000
x192
1958E
Yet Another Permutation Constructive
*special problem
,
constructive algorithms
1900
x256
1958D
Staircase
*special problem
1600
x531
1958C
Firewood
*special problem
1500
x722
1958B
Clock in the Pool
*special problem
,
math
1400
x901
1958A
1-3-5
*special problem
,
dp
1100
x1969
1957F2
Frequency Mismatch (Hard Version)
binary search
,
data structures
,
dfs and similar
,
hashing
,
probabilities
,
trees
2700
x441
1957F1
Frequency Mismatch (Easy Version)
binary search
,
data structures
,
divide and conquer
,
hashing
,
probabilities
,
trees
2600
x499
1957E
Carousel of Combinations
brute force
,
combinatorics
,
dp
,
math
,
number theory
2400
x1274
1957D
A BIT of an Inequality
bitmasks
,
brute force
,
dp
,
math
1900
x4498
1957C
How Does the Rook Move?
combinatorics
,
dp
,
math
1600
x9706
1957B
A BIT of a Construction
bitmasks
,
constructive algorithms
,
greedy
,
implementation
1100
x17982
1957A
Stickogon
constructive algorithms
,
greedy
800
x23355
1956F
Nene and the Passing Game
constructive algorithms
,
data structures
,
dsu
,
graphs
,
sortings
3000
x366
1956E2
Nene vs. Monsters (Hard Version)
brute force
,
greedy
,
implementation
,
math
2700
x887
1956E1
Nene vs. Monsters (Easy Version)
brute force
,
implementation
,
math
2500
x1470
1956D
Nene and the Mex Operator
bitmasks
,
brute force
,
constructive algorithms
,
divide and conquer
,
dp
,
greedy
,
implementation
,
math
2000
x3942
1956C
Nene's Magical Matrix
constructive algorithms
,
greedy
,
math
1600
x12944
1956B
Nene and the Card Game
games
,
greedy
800
x21270
1956A
Nene's Game
binary search
,
brute force
,
data structures
,
games
,
greedy
800
x21727
1955H
The Most Reckless Defense
bitmasks
,
brute force
,
constructive algorithms
,
dp
,
flows
,
graph matchings
,
shortest paths
2300
x1263
1955G
GCD on a grid
brute force
,
dfs and similar
,
dp
,
implementation
,
math
,
number theory
1900
x4566
1955F
Unfair Game
dp
,
games
,
greedy
,
math
,
schedules
1800
x7141
1955E
Long Inversions
brute force
,
greedy
,
implementation
,
sortings
1700
x8676
1955D
Inaccurate Subsequence Search
data structures
,
two pointers
1400
x15523
1955C
Inhabitant of the Deep Sea
greedy
,
implementation
,
math
1300
x21330
1955B
Progressive Square
constructive algorithms
,
data structures
,
implementation
,
sortings
1000
x28022
1955A
Yogurt Sale
math
800
x43682
1954F
Unique Strings
combinatorics
,
dp
,
math
3100
x254
1954E
Chain Reaction
binary search
,
data structures
,
dsu
,
greedy
,
implementation
,
math
,
number theory
2200
x2308
1954D
Colored Balls
combinatorics
,
dp
,
math
,
sortings
1800
x6215
1954C
Long Multiplication
greedy
,
math
,
number theory
1200
x19504
1954B
Make It Ugly
implementation
,
math
1200
x18644
1954A
Painting the Ribbon
constructive algorithms
,
greedy
,
math
900
x24228
1951I
Growing Trees
binary search
,
constructive algorithms
,
flows
,
graphs
,
greedy
3200
x76
1951H
Thanos Snap
binary search
,
dp
,
games
,
greedy
,
trees
3200
x280
1951G
Clacking Balls
combinatorics
,
math
,
probabilities
3100
x336
1951F
Inversion Composition
constructive algorithms
,
data structures
,
greedy
2500
x766
1951E
No Palindromes
brute force
,
constructive algorithms
,
divide and conquer
,
greedy
,
hashing
,
implementation
,
math
,
strings
2000
x3655
1951D
Buying Jewels
constructive algorithms
,
greedy
,
math
2000
x5429
1951C
Ticket Hoarding
greedy
,
math
,
sortings
1400
x11717
1951B
Battle Cows
binary search
,
data structures
,
greedy
1200
x14676
1951A
Dual Trigger
constructive algorithms
,
greedy
,
math
900
x19781
1950G
Shuffling Songs
bitmasks
,
dfs and similar
,
dp
,
graphs
,
hashing
,
implementation
,
strings
1900
x4406
1950F
0, 1, 2, Tree!
bitmasks
,
brute force
,
greedy
,
implementation
,
trees
1700
x9194
1950E
Nearly Shortest Repeating Substring
brute force
,
implementation
,
number theory
,
strings
1500
x14508
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