NP-Hard Problem

dfs and similar, graphs

Lunar New Year and a Wander

data structures, dfs and similar, graphs, greedy, shortest paths

Bear and Friendship Condition

dfs and similar, dsu, graphs

K-Complete Word

dfs and similar, dsu, greedy, implementation, strings

Journey

dfs and similar, dp, graphs, probabilities, trees

Binary String Reconstruction

constructive algorithms, dfs and similar, math

Cyclic Components

dfs and similar, dsu, graphs

Kefa and Park

dfs and similar, graphs, trees

Robot Factory

bitmasks, dfs and similar

Send the Fool Further! (easy)

dfs and similar, graphs, trees

Serial Time!

dfs and similar, dsu

Om Nom and Dark Park

dfs and similar, greedy, implementation

Dorm Water Supply

dfs and similar, graphs

Sorting by Subsequences

dfs and similar, dsu, implementation, math, sortings

Strongly Connected City

brute force, dfs and similar, graphs, implementation

Connect

brute force, dfs and similar, dsu

Swap Adjacent Elements

dfs and similar, greedy, math, sortings, two pointers

Set Construction

constructive algorithms, dfs and similar, graphs, greedy

Where is the Pizza?

data structures, dfs and similar, dsu, graphs, implementation, math

Phase Shift

dfs and similar, dsu, graphs, greedy, implementation, strings

Anonymous Informant

brute force, dfs and similar, graphs, implementation

Queen

dfs and similar, trees

Mr. Kitayuta's Colorful Graph

dfs and similar, dp, dsu, graphs

DZY Loves Chemistry

dfs and similar, dsu, greedy

Copil Copac Draws Trees

dfs and similar, dp, graphs, trees

Fillomino 2

constructive algorithms, dfs and similar, greedy, implementation

Not Assigning

constructive algorithms, dfs and similar, number theory, trees

News Distribution

dfs and similar, dsu, graphs

Soldier and Cards

brute force, dfs and similar, games

Divide by three, multiply by two

dfs and similar, math, sortings

Learning Languages

dfs and similar, dsu

Two Buttons

dfs and similar, graphs, greedy, implementation, math, shortest paths

Square Earth?

dfs and similar, greedy, implementation

Bear and Compressing

brute force, dfs and similar, dp, strings

Tournament

bitmasks, brute force, dfs and similar, greedy

Recursive Queries

binary search, data structures, dfs and similar

Neko Performs Cat Furrier Transform

bitmasks, constructive algorithms, dfs and similar, math

Xor-tree

dfs and similar, trees

Anji's Binary Tree

dfs and similar, dp, trees

Permutation Game

brute force, dfs and similar, games, graphs, greedy, math

Plus from Picture

dfs and similar, implementation, strings

PolandBall and Forest

dfs and similar, dsu, graphs, interactive, trees

White-Black Balanced Subtrees

dfs and similar, dp, graphs, trees

Arrow Path

brute force, constructive algorithms, dfs and similar, dp, graphs, shortest paths

Masha and a Beautiful Tree

dfs and similar, divide and conquer, graphs, sortings, trees

Mahmoud and Ehab and the bipartiteness

dfs and similar, graphs, trees

Forever Winter

dfs and similar, graphs, math

Books Exchange (hard version)

dfs and similar, dsu, math

Getting Zero

bitmasks, brute force, dfs and similar, dp, graphs, greedy, shortest paths

Rumor

dfs and similar, graphs, greedy

Coloring a Tree

dfs and similar, dsu, greedy

Students and Shoelaces

brute force, dfs and similar, graphs, implementation

Reposts

*special problem, dfs and similar, dp, graphs, trees

Rudolf and the Ball Game

dfs and similar, dp, implementation

Apple Tree

combinatorics, dfs and similar, dp, math, trees

Fall Down

dfs and similar, implementation

WeirdSort

dfs and similar, sortings

Permutation Transformation

dfs and similar, divide and conquer, implementation

Ice Skating

brute force, dfs and similar, dsu, graphs

Districts Connection

constructive algorithms, dfs and similar

DZY Loves Chessboard

dfs and similar, implementation

BerSU Ball

dfs and similar, dp, graph matchings, greedy, sortings, two pointers

Путь Робота

constructive algorithms, dfs and similar, graphs

Game on Ranges

brute force, dfs and similar, implementation, sortings

The Lakes

dfs and similar, dsu, graphs, implementation

Frog Jumps

binary search, data structures, dfs and similar, greedy, implementation

King Escape

dfs and similar, graphs, implementation

Transformation: from A to B

brute force, dfs and similar, math

Badge

brute force, dfs and similar, graphs

Gold Rush

brute force, dfs and similar, dp, implementation

New Year Transportation

dfs and similar, graphs, implementation

Bmail Computer Network

*special problem, dfs and similar, trees

Protect Sheep

brute force, dfs and similar, graphs, implementation

Make it Divisible by 25

dfs and similar, dp, greedy, math, math

Party

dfs and similar, graphs, trees

The Way to Home

dfs and similar, dp, greedy, implementation

Computer Game

brute force, dfs and similar, dp, implementation

Gregor and the Pawn Game

dfs and similar, dp, flows, graph matchings, graphs, greedy, implementation