Finding Zero

constructive algorithms, interactive, math

Perfect Matching

data structures, divide and conquer, interactive, trees

Spanning Tree Queries

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

Make Them Equal

dp, greedy

Distance Tree (hard version)

binary search, dfs and similar, shortest paths, 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

Strange Test

binary search, bitmasks, brute force, dp, math

Making It Bipartite

flows, graph matchings, graphs, number theory

Expected Components

combinatorics, math, number theory, probabilities

Flipping Range

constructive algorithms, dp, greedy, number theory

Paint the Middle

dp, greedy, sortings, two pointers

Range and Partition

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

Spaceship Crisis Management

binary search, data structures, geometry, sortings

Groceries in Meteor Town

binary search, data structures, dsu, trees

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

Peculiar Movie Preferences

greedy, strings

Not Splitting

geometry, graphs, greedy, implementation, shortest paths

Not Escaping

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

Not Adding

brute force, dp, math, number theory

A Random Code Problem

combinatorics, dp, math, number theory, probabilities

Black and White Tree

dfs and similar, greedy, trees

Martial Arts Tournament

binary search, brute force, greedy, math

Monsters And Spells

binary search, data structures, dp, greedy, implementation, math, two pointers

Cats on the Upgrade (hard version)

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

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

Road Optimization

dp

MinOr Tree

bitmasks, dfs and similar, dsu, graphs, greedy

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

Balanced Stone Heaps

binary search, greedy

Quadratic Set

constructive algorithms, hashing, math, number theory

Math Test

bitmasks, brute force, greedy

Shuffle

combinatorics, math, two pointers

Set or Decrease

binary search, brute force, greedy, sortings

Two Sequences

data structures, hashing, string suffix structures

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Weighted Increasing Subsequences

data structures, dp, math

Strange Instructions

data structures, greedy, implementation

New School

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

The Winter Hike

constructive algorithms, greedy, math

Hidden Permutations

dfs and similar, interactive, math

Subsequences Galore

bitmasks, combinatorics, dp

Bipartite Array

dp, greedy

Replace the Numbers

constructive algorithms, data structures, dsu, implementation

Exact Change

brute force, constructive algorithms, greedy

BA-String

brute force, dp, greedy, implementation, math

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

MEX and Increments

constructive algorithms, data structures, dp, greedy, implementation, math, sortings

New Year's Problem

binary search, greedy, sortings

Trader Problem

data structures, dsu, greedy, sortings

Reverse

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

Singers' Tour

constructive algorithms, math

Christmas Chocolates

dfs and similar, dp, games, graphs, implementation, math, number theory, shortest paths, trees

Too Many Impostors (hard version)

constructive algorithms, implementation, interactive, math

Too Many Impostors (easy version)

constructive algorithms, implementation, interactive

Keep XOR Low

bitmasks, combinatorics, data structures, divide and conquer, dp, math

Just Add an Edge

dfs and similar, dp, graphs

Tricolor Triangles

brute force, graphs, math, matrices

Lexicographically Small Enough

brute force, data structures, greedy, strings

Keep the Average High

dp, greedy, math

Reindeer Games

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

Maximum Adjacent Pairs

constructive algorithms, graph matchings

LEGOndary Grandmaster

combinatorics, dp, 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

Menorah

brute force, graphs, greedy, math

Divan and a Cottage

binary search, data structures

Divan and Kostomuksha (hard version)

dp, number theory

Divan and Kostomuksha (easy version)

dp, number theory

Tree Coloring

combinatorics, divide and conquer, fft

Crazy Robot

dfs and similar, graphs

MEX Sequences

dp, math

Max Sum Array

combinatorics, constructive algorithms, greedy, sortings

Armor and Weapons

brute force, dp, greedy, shortest paths

Messages

brute force, dp, greedy, probabilities, sortings

X-Magic Pair

math, number theory

Robot and Candies

data structures, graph matchings, greedy

ATM and Students

binary search, data structures, two pointers

Escape The Maze (hard version)

dfs and similar, dp, greedy, shortest paths, trees

Escape The Maze (easy version)

dfs and similar, greedy, shortest paths, trees, two pointers

Mashtali vs AtCoder

games, trees

Squid Game

data structures, dfs and similar, greedy, trees

AmShZ Wins a Bet

data structures, greedy, hashing

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

AmShZ and G.O.A.T.

binary search, brute force, greedy, implementation, math

Not Quite Lee

combinatorics, dp, math, number theory

Keshi Is Throwing a Party

binary search, greedy

Pushing Robots

A Stroll Around the Matrix

data structures, greedy, math

Interesting Sections

data structures, divide and conquer, meet-in-the-middle, two pointers

William The Oblivious

bitmasks, data structures, dp, matrices

Social Network

dsu, graphs, greedy, implementation, trees