Same GCDs

math, number theory

Obtain The String

dp, greedy, strings

Infinite Prefixes

math, strings

Three Paths on a Tree

dfs and similar, dp, greedy, trees

Obtain a Permutation

greedy, implementation, math

MEX maximizing

data structures, greedy, implementation, math

Nora's Toy Boxes

bitmasks, combinatorics, dp

Rin and The Unknown Flower

constructive algorithms, greedy, interactive, math

Chaotic V.

dp, graphs, greedy, math, number theory, trees

Xenon's Attack on the Gangs

combinatorics, dfs and similar, dp, greedy, trees

Aroma's Search

brute force, constructive algorithms, geometry, greedy, implementation

Coffee Varieties (easy version)

graphs, interactive

Making Shapes

dp

Cartesian Tree

data structures

Coffee Varieties (hard version)

constructive algorithms, graphs, interactive

Prefix Enlightenment

dfs and similar, dsu, graphs

Irreducible Anagrams

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

Mind Control

brute force, data structures, implementation

Red-Blue Graph

constructive algorithms, flows

Messenger Simulator

data structures

Minimax Problem

binary search, bitmasks, dp

Two Arrays

combinatorics, dp

Harry The Potter

brute force, constructive algorithms, dp, fft, implementation, math

Fedya the Potter Strikes Back

data structures, strings

LCC

data structures, math, matrices, probabilities

Madhouse (Hard version)

brute force, constructive algorithms, hashing, interactive, math

Madhouse (Easy version)

brute force, constructive algorithms, interactive, math

Numbers on Tree

constructive algorithms, data structures, dfs and similar, graphs, greedy, trees

Garland

dp, greedy, sortings

Classical?

binary search, combinatorics, number theory

Delete a Segment

brute force, constructive algorithms, data structures, dp, graphs, sortings, trees, two pointers

Dr. Evil Underscores

bitmasks, brute force, dfs and similar, divide and conquer, dp, greedy, strings, trees

Seollal

graphs

New Year and Social Network

data structures, graph matchings, graphs, math, trees

New Year and Castle Construction

combinatorics, geometry, math, sortings

New Year and Conference

binary search, data structures, hashing, sortings

New Year and Permutation

combinatorics, math

DIY Garland

constructive algorithms, greedy, trees

New Year Parties

dp, greedy

Christmas Trees

graphs, greedy, shortest paths

The Cake Is a Lie

constructive algorithms, data structures, dfs and similar, graphs

Enchanted Artifact

constructive algorithms, interactive, strings

Petya and Exam

greedy, sortings, two pointers

K for the Price of One (Hard Version)

dp, greedy, sortings

Azamon Web Services

greedy

Intergalactic Sliding Puzzle

combinatorics, constructive algorithms, math

Kirchhoff's Current Loss

math

Miss Punyverse

dp, greedy, trees

Jeremy Bearimy

dfs and similar, graphs, greedy, trees

Beingawesomeism

implementation, math

Cut and Paste

implementation, math

New Year and Handle Change

binary search, dp

New Year Permutations

combinatorics, dp

Santa's Bot

combinatorics, math, probabilities

Cards

combinatorics, dp, math, number theory, probabilities

Tests for problem D

constructive algorithms, dfs and similar, divide and conquer, trees

Segment Tree

data structures, dsu, graphs, trees

Berry Jam

data structures, dp, greedy, implementation

Let's Play the Words?

data structures, hashing, implementation, math

Asterisk Substrings

string suffix structures

Four Stones

constructive algorithms

Tree Elimination

dp, trees

Beautiful Rectangle

brute force, combinatorics, constructive algorithms, data structures, greedy, math

Two Fairs

combinatorics, dfs and similar, dsu, graphs

Two Bracket Sequences

dp, strings, two pointers

Nearest Opposite Parity

dfs and similar, graphs, shortest paths

Divide The Students

brute force

Common Number

binary search, combinatorics, dp, math

Portals

data structures, dp, greedy, implementation, sortings

Xor on Figures

constructive algorithms, fft, math

Number of Components

data structures

Subset with Zero Sum

constructive algorithms, dfs and similar, graphs, math

Awesome Substrings

math, strings

Divide Points

constructive algorithms, geometry, math

Strange Device

constructive algorithms, interactive, math, sortings

Happy Cactus

dp

Invertation in Tournament

brute force, divide and conquer, graphs, math

K Integers

binary search, data structures

Domino for Young

dp, greedy, math

Long Beautiful Integer

constructive algorithms, greedy, implementation, strings

Lexicography

constructive algorithms, strings

Key Storage

combinatorics, math

Just Arrange the Icons

greedy, implementation, math

Intriguing Selection

brute force, constructive algorithms, implementation, interactive, sortings

Help BerLine

constructive algorithms

Game Relics

math, probabilities

Foolprüf Security

graphs

Elections

greedy

DevOps Best Practices

constructive algorithms

Cactus Revenge

constructive algorithms

Apprentice Learning Trajectory

Red-Blue Graph

dp, graphs, math, matrices, meet-in-the-middle

Permutation Concatenation

string suffix structures

Almost Same Distance

dfs and similar, graphs

Spaceship Solitaire

data structures, greedy, implementation

Decreasing Debts

constructive algorithms, data structures, graphs, greedy, implementation, math, two pointers

Beautiful Mirrors

data structures, dp, math, probabilities

Beautiful Fibonacci Problem

constructive algorithms, number theory

Beautiful League

constructive algorithms, flows, graph matchings

Beautiful Bracket Sequence (hard version)

combinatorics, probabilities