Twin Permutations

constructive algorithms

The Third Grace

data structures, dp

Bully Sort

data structures, math

Mex Tree

brute force, dp, trees

Hyperregular Bracket Strings

combinatorics, greedy, hashing, math, number theory, sortings

The BOSS Can Count Pairs

brute force, math

Copil Copac Draws Trees

dfs and similar, dp, graphs, trees

Don't Blame Me

bitmasks, combinatorics, dp, math

Hits Different

data structures, dp, implementation, math

Forever Winter

dfs and similar, graphs, math

The Lakes

dfs and similar, dsu, graphs, implementation

Gold Rush

brute force, dfs and similar, dp, implementation

Mr. Perfectly Fine

bitmasks, greedy, implementation

Blank Space

implementation

Love Story

implementation, strings

Permutation Swap

math, number theory

Divisible Array

constructive algorithms, math

Copium Permutation

constructive algorithms, data structures, greedy

Bus Routes

binary search, constructive algorithms, dfs and similar, greedy, trees

Two Centroids

data structures, dfs and similar, greedy, trees

Palindrome Partition

binary search, brute force, data structures, dp, hashing, strings

Range Sorting (Hard Version)

binary search, data structures, dp, greedy

Range Sorting (Easy Version)

binary search, dp, dsu, greedy, trees, two pointers

Counting Orders

combinatorics, math, sortings, two pointers

Fading into Fog

geometry, interactive, math, probabilities

Walk the Runway

bitmasks, brute force, data structures, dp, graphs, implementation, sortings

Running Miles

brute force, dp, greedy

Dreaming of Freedom

greedy, math, number theory

Lunatic Never Content

math, number theory

Trust Nobody

brute force, greedy, implementation, sortings

LuoTianyi and the Table

greedy, math

LuoTianyi and the Palindrome String

greedy, strings

LuoTianyi and Cartridge

data structures, trees

LuoTianyi and the Function

data structures

LuoTianyi and XOR-Tree

data structures, dfs and similar, dp, dsu, greedy, trees

LuoTianyi and the Floating Islands (Hard Version)

combinatorics, dfs and similar, math, probabilities, trees

LuoTianyi and the Floating Islands (Easy Version)

combinatorics, math, probabilities, trees

LuoTianyi and the Show

greedy, implementation

Random Walk

dp, graphs, math, probabilities, trees

Removing Graph

brute force, dp, games, graphs, math

Unique Palindromes

constructive algorithms, math, strings

Strongly Composite

greedy, math, number theory

Sort with Step

brute force, math, sortings

A-characteristic

combinatorics, constructive algorithms, math

Magic Triples (Hard Version)

brute force, data structures, math, number theory

Magic Triples (Easy Version)

brute force, data structures, math, number theory

Gardening Friends

brute force, dfs and similar, dp, graphs, trees

Making Anti-Palindromes

greedy, math, strings

Super-Permutation

constructive algorithms, math

Bun Lover

math

Karina and Array

greedy, math, sortings

TubeTube Feed

brute force, implementation

Timber

combinatorics, dp, fft, math

Rearrange Brackets

brute force, dp, greedy, sortings, strings

Black Cells

binary search, brute force, greedy, math

Tear It Apart

brute force, implementation, math, strings

Sort the Subarray

brute force, greedy

Matching

combinatorics, math

JoJo's Incredible Adventures

math, strings, two pointers

Yura's New Name

implementation, strings

Willy-nilly, Crack, Into Release!

data structures, dp

Roads in E City

interactive, math, probabilities, trees

Misha and Apples

brute force, data structures, dp, two pointers

The Fox and the Complete Tree Traversal

constructive algorithms, dp, implementation, math, trees

The Butcher

geometry, greedy, implementation, sortings, two pointers

Constructive Problem

brute force, greedy

Indivisible

constructive algorithms

Politics

greedy, implementation

Entangled Substrings

string suffix structures, strings

Half-sum

brute force, divide and conquer, greedy

Toy Machine

constructive algorithms, games, implementation

Similar Polynomials

combinatorics, math

Fish Graph

brute force, constructive algorithms, dfs and similar, graphs

Almost Increasing Subsequence

binary search, data structures, greedy

Grid Reconstruction

constructive algorithms, greedy

Ian Visits Mary

constructive algorithms, geometry, number theory

OH NO1 (-2-3-4)

constructive algorithms, graphs, math

Bosco and Particle

dp, math, number theory, strings

XOR Counting

bitmasks, combinatorics, dp, math

Between

constructive algorithms, dfs and similar, graphs, greedy

Sum Graph

brute force, constructive algorithms, graphs, implementation, interactive, shortest paths, trees

Ian and Array Sorting

greedy, math

Communication Towers

brute force, divide and conquer, dsu

Chain Chips

data structures, dp, matrices

Balancing Weapons

binary search, brute force, data structures, math, two pointers

Search in Parallel

constructive algorithms, greedy, sortings

Long Legs

brute force, math

Coins

implementation, math

Unmysterious Language

*special problem, constructive algorithms, strings

Mountain Climber

*special problem

Expected Twist

*special problem, interactive

Colour Vision

*special problem, implementation

Factorization

*special problem, number theory

Not a Geometry Problem

*special problem, *special problem, constructive algorithms, geometry, math

Trivial Conjecture

*special problem, constructive algorithms, math, number theory

Digits

*special problem

Was it Rated?

*special problem, *special problem, *special problem, brute force, implementation

Are You a Robot?

*special problem, *special problem, *special problem, expression parsing, strings

Vlad and the Nice Paths (hard version)

binary search, combinatorics, data structures, dp, math, two pointers

Vlad and the Nice Paths (easy version)

combinatorics, dp, math