Everyone Loves to Sleep

implementation, math

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

Build Permutation

constructive algorithms, dp, math

Optimal Reduction

constructive algorithms, sortings

Traveling Salesman Problem

geometry, greedy, implementation

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

Sort Zero

greedy, sortings

Woeful Permutation

constructive algorithms, greedy, number theory

Wonderful Permutation

greedy, implementation

Party

brute force, graphs

Perfect Permutation

constructive algorithms

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

Color the Picture

constructive algorithms, greedy, 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

Also Try Minecraft

data structures, dp, implementation

Three Doors

brute force, greedy, implementation, math

Difference of GCDs

constructive algorithms, math

Difference Operations

greedy, math

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

Qpwoeirut And The City

dp, flows, greedy, implementation

Making Towers

dp, greedy, math

Another String Minimization Problem

2-sat, constructive algorithms, greedy, string suffix structures, strings

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

Mark and His Unfinished Essay

brute force, implementation

Mark the Dust Sweeper

constructive algorithms, greedy, implementation

Mark the Photographer

greedy, 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

Virus

greedy, implementation, sortings

Luke is a Foodie

brute force, greedy, implementation

Two 0-1 Sequences

constructive algorithms, greedy

Good Key, Bad Key

bitmasks, brute force, dp, greedy, math

Yet Another Problem About Pairs Satisfying an Inequality

binary search, data structures, dp, greedy, sortings

Mirror Grid

implementation

Double Strings

brute force, data structures, strings

Cypher

brute force, implementation, strings

ICPC Balloons

data structures, implementation

YES or YES?

brute force, implementation, strings

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

Not a Cheap String

greedy

Train and Queries

data structures, greedy

Polycarp Writes a String from Memory

greedy

Round Down the Price

constructive algorithms

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

Schedule Management

binary search, greedy, implementation, two pointers

Permutation

greedy

Grass Field

implementation

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

Palindromic Numbers

constructive algorithms, implementation, math

Optimal Path

constructive algorithms, greedy, math

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

Almost Ternary Matrix

bitmasks, constructive algorithms, matrices

The Third Three Number Problem

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

3SUM Closure

brute force, data structures

Rising Sand

constructive algorithms, greedy, implementation

XOR Mixup

bitmasks, brute force

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

awoo's Favorite Problem

binary search, constructive algorithms, data structures, greedy, implementation, strings, two pointers

Promo

greedy, sortings