Remove Directed Edges

dfs and similar, dp, graphs

Breaking the Wall

binary search, brute force, constructive algorithms, greedy, math

Anti-Theft Road Planning

bitmasks, constructive algorithms, divide and conquer, greedy, interactive, math

Power or XOR?

bitmasks, combinatorics, math, number theory

Array Shuffling

constructive algorithms, graphs, greedy

notepad.exe

binary search, constructive algorithms, greedy, interactive

Preorder

combinatorics, divide and conquer, dp, dsu, hashing, sortings, trees

Jee, You See?

bitmasks, combinatorics, dp

Hemose on the Tree

bitmasks, constructive algorithms, dfs and similar, trees

Half Queen Cover

constructive algorithms, math

Optimal Partition

data structures, dp

Job Lookup

constructive algorithms, dp, shortest paths, trees

Interactive Treasure Hunt

brute force, constructive algorithms, geometry, interactive, math

Fancy Stack

combinatorics, dp, implementation

Even Split

binary search, constructive algorithms, greedy, math

MinimizOR

bitmasks, brute force, data structures, divide and conquer, greedy, implementation, two pointers

GCD Guess

bitmasks, chinese remainder theorem, constructive algorithms, games, interactive, math, number theory

Narrow Components

brute force, data structures, dp, dsu, math, trees

Promising String (hard version)

data structures, implementation, math, strings

AND-MEX Walk

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

Gojou and Matrix Game

data structures, dp, games, hashing, implementation, math, number theory, sortings

388535 (Hard Version)

bitmasks, brute force, data structures, math

Star MST

combinatorics, dp, graph matchings, math

For Gamers. By Gamers.

binary search, brute force, greedy, math, sortings

Equal Tree Sums

constructive algorithms, dfs and similar, math, trees

Arithmetic Operations

brute force, data structures, graphs, math

Potion Brewing Class

dfs and similar, math, number theory, trees

Counting Shortcuts

data structures, dfs and similar, dp, graphs, shortest paths

Vitaly and Advanced Useless Algorithms

dp, greedy, implementation

Madoka and the Sixth-graders

data structures, dfs and similar, greedy

Power Board

brute force, dp, math, number theory

Weight the Tree

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

Anonymity Is Important

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

Repetitions Decoding

constructive algorithms, implementation, sortings

Colorful Operations

brute force, data structures, implementation

Big Brush

constructive algorithms, data structures, greedy, implementation

Towers

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

Best Pair

binary search, brute force, implementation

Cars

2-sat, constructive algorithms, dfs and similar, dsu, graphs, greedy, sortings

Fair Share

constructive algorithms, data structures, dfs and similar, graph matchings, graphs

Finding Zero

constructive algorithms, interactive, math

Spanning Tree Queries

binary search, data structures, dfs and similar, dsu, graphs, greedy, math, sortings, trees

Distance Tree (easy version)

binary search, data structures, dfs and similar, graphs, shortest paths, trees

New Year Concert

binary search, data structures, greedy, math, number theory, two pointers

Flipping Range

constructive algorithms, dp, greedy, number theory

Paint the Middle

dp, greedy, sortings, two pointers

Game on Sum (Hard Version)

combinatorics, dp, games, math

Game on Sum (Easy Version)

combinatorics, dp, games, math

Grid Xor

constructive algorithms, greedy, implementation, interactive, math

Not Escaping

data structures, dp, implementation, shortest paths, two pointers

Black and White Tree

dfs and similar, greedy, trees

Martial Arts Tournament

binary search, brute force, greedy, math

Cats on the Upgrade (easy version)

brute force, data structures, dfs and similar, divide and conquer, dp, graphs, trees

Binary Spiders

bitmasks, data structures, implementation, math, sortings, trees

Interacdive Problem

binary search, constructive algorithms, interactive

Masha-forgetful

brute force, constructive algorithms, dp, hashing, implementation, strings

Middle Duplication

data structures, dfs and similar, greedy, strings, trees

Robot Cleaner Revisit

implementation, math, probabilities

Math Test

bitmasks, brute force, greedy

Shuffle

combinatorics, math, two pointers

New School

binary search, data structures, dp, greedy, implementation, sortings

The Winter Hike

constructive algorithms, greedy, math

Subsequences Galore

bitmasks, combinatorics, dp

Exact Change

brute force, constructive algorithms, greedy

Permutation and Queries

brute force, data structures, divide and conquer, two pointers

Unusual Minesweeper

binary search, dfs and similar, dsu, greedy, sortings

Let's Play the Hat?

brute force, constructive algorithms, greedy, math

Trader Problem

data structures, dsu, greedy, sortings

Reverse

bitmasks, constructive algorithms, dfs and similar, implementation, math, strings

Too Many Impostors (hard version)

constructive algorithms, implementation, interactive, math

Lexicographically Small Enough

brute force, data structures, greedy, strings

Keep the Average High

dp, greedy, math

Purple Crayon

data structures, dfs and similar, games, graphs, greedy, math, sortings, trees

X(or)-mas Tree

bitmasks, dfs and similar, dsu, graphs, trees

Divan and Kostomuksha (hard version)

dp, number theory

Divan and Kostomuksha (easy version)

dp, number theory

Crazy Robot

dfs and similar, graphs

Max Sum Array

combinatorics, constructive algorithms, greedy, sortings

Messages

brute force, dp, greedy, probabilities, sortings

Robot and Candies

data structures, graph matchings, greedy

AmShZ and G.O.A.T.

binary search, brute force, greedy, implementation, math

Not Quite Lee

combinatorics, dp, math, number theory

William The Oblivious

bitmasks, data structures, dp, matrices

Dominoes

combinatorics, fft, graphs, math, number theory

Banquet Preparations 2

greedy, sortings, two pointers

Banquet Preparations 1

greedy

Robot on the Board 2

brute force, dfs and similar, graphs, implementation

Arena

combinatorics, dp, math

Red-Blue Matrix

brute force, constructive algorithms, implementation, sortings

Array Equalizer

binary search, greedy, implementation, math, number theory, sortings, two pointers

Treelabeling

bitmasks, constructive algorithms, dfs and similar, games, greedy, implementation, trees

Extreme Extension

dp, greedy, math, number theory

Optimal Insertion

data structures, divide and conquer, dp, greedy, sortings

Party Organization

brute force, math, probabilities

Hidden Fortress

interactive, math

Bubble Strike

combinatorics, math, probabilities, ternary search

RBS

binary search, bitmasks, brute force, data structures, dp

Staircases

brute force, combinatorics, data structures, dfs and similar, dp, implementation, math

Ideal Farm

constructive algorithms, math

Rubik's Cube Coloring (hard version)

brute force, dp, implementation, math, trees