The Winter Hike

constructive algorithms, greedy, math

Hidden Permutations

dfs and similar, interactive, math

Integers Shop

data structures, greedy, implementation

Stable Arrangement of Rooks

constructive algorithms

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

Triangles on a Rectangle

geometry, greedy, math

Equal or Not Equal

constructive algorithms, dsu, implementation

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

Wrong Addition

implementation

Squares and Cubes

implementation, math

Square String?

implementation, strings

Trader Problem

data structures, dsu, greedy, sortings

Reverse

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

Singers' Tour

constructive algorithms, math

Array and Operations

dp, greedy, math

Paint the Array

math

Missing Bigram

implementation

Polycarp and Sums of Subsequences

math, sortings

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

Paprika and Permutation

binary search, greedy, math, sortings

GCD Problem

brute force, constructive algorithms, math, number theory

Forbidden Subsequence

constructive algorithms, greedy, sortings, strings

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

Mirror in the String

greedy, strings

Integer Diversity

implementation

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

And It's Non-Zero

bitmasks, greedy, math

Closing The Gap

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

Divan and a New Project

constructive algorithms, sortings

Divan and a Store

brute force, constructive algorithms, greedy

Tree Coloring

combinatorics, divide and conquer, fft

Crazy Robot

dfs and similar, graphs

MEX Sequences

dp, math

Poisoned Dagger

binary search

Absent Remainder

greedy, implementation, sortings

Long Comparison

implementation, 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

Chat Ban

binary search, math

Special Permutation

constructive algorithms, greedy

Distance

brute force, constructive algorithms

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

Polycarp Recovers the Permutation

constructive algorithms

Team Composition: Programmers and Mathematicians

binary search, constructive algorithms, math

Make Even

constructive algorithms, math

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

Kalindrome Array

greedy, two pointers

Anti Light's Cell Guessing

math

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

William the Vigilant

implementation, strings

Divide and Multiply

greedy, implementation, math, number theory

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

Build the Permutation

constructive algorithms, greedy

Find Array

constructive algorithms, math

Banquet Preparations 2

greedy, sortings, two pointers