Build a Tree and That Is It

constructive algorithms, implementation, trees

Color with Occurrences

brute force, data structures, dp, greedy, strings

Lost Array

bitmasks, combinatorics, constructive algorithms, dp, math

Cross Swapping

2-sat, data structures, dsu, greedy, matrices

Tournament Countdown

constructive algorithms, greedy, interactive, number theory, probabilities

Triameter

binary search, data structures, dfs and similar, trees

LCM Sum (hard version)

brute force, data structures, math, number theory, two pointers

LCM Sum (easy version)

binary search, brute force, combinatorics, math, number theory, two pointers

Empty Graph

binary search, constructive algorithms, data structures, greedy, shortest paths

Two Arrays

binary search, games, graph matchings

Recover the Tree

constructive algorithms, trees

XOR Triangle

bitmasks, brute force, constructive algorithms, dp, greedy, math

Rain

binary search, brute force, data structures, geometry, greedy, implementation, math

Multiset of Strings

bitmasks, brute force, dp, fft, flows, graphs, math, meet-in-the-middle, trees

XOR Tree

bitmasks, data structures, dfs and similar, dsu, greedy, trees

Rorororobot

binary search, data structures, greedy, math

Recover an RBS

constructive algorithms, greedy, implementation, strings

Bugaboo

bitmasks, constructive algorithms, dp, number theory

Replace

binary search, data structures

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

DFS Trees

dfs and similar, dsu, graphs, greedy, sortings, trees

Difference Array

brute force, data structures, implementation, sortings

Doremy's IQ

binary search, constructive algorithms, greedy, implementation

Qpwoeirut and Vertices

binary search, data structures, dfs and similar, divide and conquer, dsu, greedy, trees

Chopping Carrots (Hard Version)

brute force, constructive algorithms, data structures, dp, greedy, math, number theory, two pointers

Chopping Carrots (Easy Version)

binary search, brute force, constructive algorithms, greedy, number theory

Mark and the Online Exam

bitmasks, constructive algorithms, interactive, probabilities

Mark and Professor Koro

binary search, bitmasks, brute force, combinatorics, data structures, greedy

Mark and Lightbulbs

combinatorics, constructive algorithms, greedy, math, sortings

Game of AI (hard version)

combinatorics, fft, math

Game of AI (easy version)

combinatorics, constructive algorithms, dp, fft, math

Mio and Lucky Array

constructive algorithms, fft, math, strings

Colouring Game

constructive algorithms, dp, games

Count Seconds

brute force, constructive algorithms, dp, graphs, implementation, math

Magical Array

constructive algorithms, hashing, implementation, math

Good Key, Bad Key

bitmasks, brute force, dp, greedy, math

Passable Paths (hard version)

data structures, dfs and similar, trees

Passable Paths (easy version)

dfs and similar, trees

Equate Multisets

constructive algorithms, data structures, greedy, math, number theory

Split Into Two Sets

dfs and similar, dsu, graphs

Points

combinatorics, data structures, implementation, math, matrices

Text Editor

brute force, dp, greedy, strings

Permutation Restoration

binary search, data structures, greedy, math, sortings, two pointers

Puzzle

constructive algorithms, dp, greedy

Serega the Pirate

brute force, constructive algorithms

River Locks

binary search, dp, greedy, math

Helping the Nature

constructive algorithms, data structures, greedy

Three Days Grace

data structures, dp, greedy, math, number theory, two pointers

Almost Triple Deletions

data structures, dp, greedy

The Third Problem

combinatorics, constructive algorithms, math

Long Binary String

bitmasks, math, matrices, meet-in-the-middle, number theory

Equal Reversal

constructive algorithms, graphs, implementation, math

PermutationForces II

brute force, combinatorics, greedy, sortings, trees, two pointers

Fixed Point Guessing

binary search, constructive algorithms, interactive

Too Many Constraints

2-sat, constructive algorithms, graphs, implementation

Coloring

brute force, combinatorics, constructive algorithms, dp, geometry, graphs, greedy, implementation, math

Guess The String

binary search, constructive algorithms, interactive

Maximum Product?

brute force, combinatorics, dp, greedy, implementation, math, two pointers

Fishingprince Plays With Array Again

brute force, data structures, geometry, math

Tree Recovery

brute force, constructive algorithms, dfs and similar, dsu, graphs, trees

Placing Jinas

combinatorics, math

Permutation Graph

binary search, constructive algorithms, data structures, divide and conquer, greedy, shortest paths

Ambiguous Dominoes

constructive algorithms, dfs and similar, graphs

Tree Queries (Hard Version)

constructive algorithms, dfs and similar, dp, greedy, trees

Tree Queries (Easy Version)

brute force, constructive algorithms, dfs and similar, dp, greedy, trees

Zero Path

brute force, data structures, dp, graphs, greedy, shortest paths

I Might Be Wrong

binary search, greedy, two pointers

Outermost Maximums

data structures, greedy

Decinc Dividing

brute force, data structures, divide and conquer, dp, greedy

Keshi in Search of AmShZ

graphs, greedy, shortest paths

Fake Plastic Trees

dfs and similar, dp, greedy, trees

Gambling

data structures, dp, greedy, math

K-Set Tree

combinatorics, dfs and similar, dp, math, trees

Number of Groups

data structures, dfs and similar, dsu, graphs, greedy, sortings

Max GEQ Sum

binary search, constructive algorithms, data structures, divide and conquer, implementation, two pointers

Count the Trains

binary search, data structures, greedy, sortings

Shifting String

graphs, math, number theory, strings

ANDfinity

bitmasks, brute force, constructive algorithms, dfs and similar, dsu, graphs

Lena and Matrix

data structures, dp, geometry, shortest paths

Infected Tree

dfs and similar, dp, trees

Manipulating History

constructive algorithms, greedy, strings

Koishi's Unconscious Permutation

fft, math

Become Big For Me

combinatorics, constructive algorithms, greedy, math, number theory

Cute number

binary search, brute force, data structures, dsu, implementation, math

Sanae and Giant Robot

binary search, brute force, data structures, dsu, greedy, sortings

Railway System

constructive algorithms, graphs, greedy, interactive, sortings

The Enchanted Forest

brute force, greedy

The Ultimate LIS Problem

data structures, greedy

Permutation Weight (Hard Version)

constructive algorithms, greedy

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Bring Balance

brute force, constructive algorithms, greedy

Linguistics

greedy, implementation, sortings, strings

Hard Cut

constructive algorithms, dfs and similar, divide and conquer, math

Euclid Guess

constructive algorithms, flows, graph matchings, math, number theory

Diverse Segments

data structures, two pointers

MEX vs DIFF

binary search, brute force, constructive algorithms, data structures, greedy, two pointers

Traps

constructive algorithms, greedy, sortings

MCMF?

data structures, flows, graphs, greedy, sortings, two pointers

Unordered Swaps

constructive algorithms, dfs and similar, graphs, greedy, math, sortings, trees

Circular Spanning Tree

constructive algorithms, implementation, trees