Long Recovery

constructive algorithms, dfs and similar

Doremy's Swapping Trees

dfs and similar, graphs, trees

Two Avenues

data structures, dfs and similar, graphs

Finding the Vertex

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

Good Graph

bitmasks, dfs and similar, graph matchings, graphs, implementation

Alphabetic Tree

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

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

New Year and Snowy Grid

dfs and similar, dsu, graphs, interactive

Just Add an Edge

dfs and similar, dp, graphs

Harder Satisfiability

2-sat, dfs and similar, graphs

Organizing a Music Festival

dfs and similar, math

Rap God

data structures, dfs and similar, hashing, strings, trees

Fake bullions

combinatorics, dfs and similar, dp, graphs, number theory

Two Sorts

binary search, dfs and similar, math, meet-in-the-middle

Iqea

data structures, dfs and similar, divide and conquer, dsu, shortest paths, trees

Island Puzzle

dfs and similar, dsu, graphs, trees

Hard Cut

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

Bus Routes

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

Grove

brute force, dfs and similar, dp, geometry, probabilities

Interactive Mex Tree

constructive algorithms, dfs and similar, interactive, trees

Harry Vs Voldemort

dfs and similar, dp, graphs, trees

Send Tree to Charlie

combinatorics, dfs and similar, dsu, trees

Bear and Chemistry

data structures, dfs and similar, graphs, trees

Cow and Vacation

dfs and similar, dsu, trees

Tree Cutting

bitmasks, dfs and similar, dp

Triameter

binary search, data structures, dfs and similar, trees

Distance Matching

constructive algorithms, dfs and similar, trees

Teleportation in Byteland

data structures, dfs and similar, divide and conquer, graphs, shortest paths, trees

Air Reform

data structures, dfs and similar, divide and conquer, dsu, graphs, implementation, trees

Chests and Keys

bitmasks, brute force, dfs and similar, dp, flows

Clockwork Bomb

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

Summer Dichotomy

2-sat, data structures, dfs and similar, greedy

Tourists

data structures, dfs and similar, graphs, trees

Sloth

dfs and similar, dp, graph matchings, trees

Just Kingdom

brute force, data structures, dfs and similar

Tree Calendar

brute force, constructive algorithms, data structures, dfs and similar, sortings, trees

Squid Game

data structures, dfs and similar, greedy, trees

Cycling City

dfs and similar, graphs

Archaeology

data structures, dfs and similar, trees

Alice and the Cactus

dfs and similar, graphs, math, probabilities

Tree and Table

dfs and similar, dp, implementation, trees

Tree and Permutation Game

dfs and similar, games, graphs, trees

Palindromic Hamiltonian Path

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

Li Hua and Path

data structures, dfs and similar, divide and conquer, dsu, trees

Berland Miners

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

The Awesomest Vertex

data structures, dfs and similar

Edge Queries

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

Around the World

bitmasks, combinatorics, dfs and similar, dp, graphs, graphs, math, trees

Down Below

binary search, dfs and similar, graphs, greedy, meet-in-the-middle, shortest paths

The Majestic Brown Tree Snake

dfs and similar, dp, greedy, trees, two pointers

A Serious Referee

bitmasks, brute force, dfs and similar, sortings

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

Falling Sand (Hard Version)

dfs and similar, dp, graphs, greedy

Game of Stacks

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

Black, White and Grey Tree

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

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

James and the Chase

dfs and similar, graphs, probabilities, trees

Tree Weights

bitmasks, constructive algorithms, data structures, dfs and similar, implementation, math, matrices, number theory, trees

Treeland and Viruses

data structures, dfs and similar, dp, shortest paths, trees

Logistical Questions

dfs and similar, divide and conquer, trees

Misha and LCP on Tree

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

Harry Potter and Moving Staircases

dfs and similar, implementation

Function Composition

dfs and similar

Wavy numbers

brute force, dfs and similar, meet-in-the-middle, sortings

Cactus Not Enough

dfs and similar, graph matchings, graphs

Problem of offices

constructive algorithms, dfs and similar, dp, trees

Bitonix' Patrol

bitmasks, brute force, combinatorics, dfs and similar, math

TOF

dfs and similar, graphs

Bear and Chase

brute force, dfs and similar, graphs, implementation, math, probabilities

Delete The Edges

brute force, constructive algorithms, dfs and similar, graphs, implementation

Almost Same Distance

dfs and similar, graphs

Snowy Mountain

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

Group Division

constructive algorithms, dfs and similar, graphs, greedy

Omkar and Pies

bitmasks, dfs and similar, dp, math, shortest paths

Doctor's Brown Hypothesis

dfs and similar, graphs, math, number theory

Wizards and Bets

dfs and similar, graphs, math, matrices

Upgrading Cities

dfs and similar, graphs

Edge Elimination

constructive algorithms, dfs and similar, dp, trees

Pumping Stations

brute force, dfs and similar, divide and conquer, flows, graphs, greedy, trees

Fairy

dfs and similar, divide and conquer, dsu

Arpa’s letter-marked tree and Mehrdad’s Dokhtar-kosh paths

data structures, dfs and similar, trees

Greedy Petya

*special problem, dfs and similar, graphs, greedy

The Overdosing Ubiquity

brute force, dfs and similar, graphs

Beautiful Tree

data structures, dfs and similar, graphs, implementation, trees

Road Repairs

dfs and similar, graphs, greedy

Matching Reduction

brute force, constructive algorithms, dfs and similar, flows, graph matchings, graphs, interactive

Tiles Placement

constructive algorithms, dfs and similar, trees

Long Way to be Non-decreasing

binary search, dfs and similar, graphs, implementation, shortest paths, two pointers

Directing Edges

dfs and similar, dp, graphs, trees

Andrey's Tree

binary search, constructive algorithms, data structures, dfs and similar, dsu, greedy, implementation, trees

Nikita and game

binary search, dfs and similar, divide and conquer, graphs, trees

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Pilgrims

dfs and similar, dp, trees

Distance to the Path

data structures, dfs and similar, trees

Rain of Fire

binary search, data structures, dfs and similar, dsu, graphs, implementation

Nezzar and Hidden Permutations

constructive algorithms, dfs and similar, graphs

Caterpillar

dfs and similar, dp, graphs, trees

Cats on the Upgrade (hard version)

binary search, data structures, dfs and similar, graphs, trees

Hidden Bipartite Graph

binary search, constructive algorithms, dfs and similar, graphs, interactive