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

Palindromes Coloring

binary search, greedy, sortings, 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

Integers Shop

data structures, greedy, implementation

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

Representative Edges

brute force, geometry, implementation, 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

Divan and bitwise operations

bitmasks, combinatorics, constructive algorithms, dp, math

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

Weights Assignment For Tree Edges

constructive algorithms, trees

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

Complex Market Analysis

binary search, dp, implementation, number theory, schedules, two pointers

Alphabetic Tree

binary search, data structures, dfs and similar, hashing, string suffix structures, strings, trees

MEX counting

combinatorics, dp, implementation

The Cells on the Paper

binary search, implementation, sortings

Dominoes

combinatorics, fft, graphs, math, number theory

Game Master

data structures, dfs and similar, dp, graphs, greedy, two pointers

Banquet Preparations 2

greedy, sortings, two pointers

Banquet Preparations 1

greedy

Robot on the Board 2

brute force, dfs and similar, graphs, implementation

Robot on the Board 1

implementation

Tree Queries

brute force, dp, trees

Arena

combinatorics, dp, math

Red-Blue Matrix

brute force, constructive algorithms, implementation, sortings

Banknotes

greedy, number theory

PalindORme

combinatorics, dp

Array Equalizer

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

Treelabeling

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