Euler tour

constructive algorithms, trees

The Shortest Statement

graphs, shortest paths, trees

Moonwalk challenge

data structures, strings, trees

Interstellar battle

math, probabilities, trees

Hyperspace Highways

dfs and similar, graphs, trees

Last chance

data structures, flows, graph matchings, graphs, trees

Intersecting Subtrees

dfs and similar, interactive, trees

Leaf Sets

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

You Are Given a Tree

data structures, dp, trees

Valid BFS?

dfs and similar, graphs, shortest paths, trees

Region Separation

combinatorics, dp, number theory, trees

Vasya and Maximum Matching

dp, trees

Recovering BST

brute force, dp, math, number theory, trees

Pisces

data structures, flows, trees

Mobile Phone Network

dfs and similar, dsu, graphs, trees

Raining season

data structures, divide and conquer, trees

Road Projects

dfs and similar, dp, trees

Tree

fft, graphs, trees

Mars rover

dfs and similar, graphs, implementation, trees

Dominant Indices

data structures, dsu, trees

Ants

2-sat, data structures, trees

Military Problem

dfs and similar, graphs, trees

Sonya and Ice Cream

binary search, data structures, dp, greedy, shortest paths, trees

Two-Paths

data structures, dp, trees

We Need More Bosses

dfs and similar, graphs, trees

Cycles in product

combinatorics, divide and conquer, trees

Cowmpany Cowmpensation

combinatorics, dp, math, trees

GCD Counting

divide and conquer, dp, dsu, number theory, trees

Flow Control

dfs and similar, dp, greedy, trees

Prince's Problem

brute force, data structures, math, number theory, trees

NN country

binary search, data structures, trees

Shark

brute force, data structures, dsu, trees

Cut 'em all!

dfs and similar, dp, graphs, greedy, trees

Useful Decomposition

implementation, trees

Cactus to Tree

dp, graphs, trees

The Number Games

data structures, greedy, trees

Kuro and GCD and XOR and SUM

binary search, bitmasks, brute force, data structures, dp, dsu, greedy, math, number theory, strings, trees

Kuro and Walking Route

dfs and similar, trees

Short Code

data structures, dp, greedy, strings, trees

Destruction of a Tree

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

Visible Black Areas

data structures, dsu, geometry, trees

Simple Cycles Edges

dfs and similar, graphs, trees

Santa's Gift

data structures, trees

Alternating Tree

combinatorics, dfs and similar, divide and conquer, dp, probabilities, trees

Full Binary Tree Queries

brute force, implementation, trees

Mahmoud and Ehab and the wrong algorithm

constructive algorithms, trees

Maximum Control (medium)

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

Heaps

dp, trees

Iqea

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

Fafa and Ancient Mathematics

dfs and similar, dp, trees

Tree

binary search, dp, trees

Peculiar apple-tree

dfs and similar, graphs, trees

Autocompletion

*special problem, strings, trees

May Holidays

data structures, trees

Public Service

constructive algorithms, graphs, trees

Perfect Security

data structures, greedy, strings, trees

Upside Down

data structures, string suffix structures, strings, trees

Stranger Trees

dp, math, matrices, trees

Jamie and Tree

data structures, trees

Jamie and To-do List

data structures, interactive, trees

Imbalance Value of a Tree

data structures, dsu, graphs, trees

Ember and Storm's Tree Game

combinatorics, dp, games, trees

Palindromes in a Tree

bitmasks, data structures, divide and conquer, trees

Christmas Spruce

implementation, trees

Tree Destruction

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

Hashing Trees

constructive algorithms, trees

Ralph And His Tour in Binary Country

brute force, data structures, trees

Subtree Minimum Query

data structures, trees

Sloth

dfs and similar, dp, graph matchings, trees

Petya and Catacombs

dsu, greedy, implementation, trees

Danil and a Part-time Job

bitmasks, data structures, trees

Restore the Tree

graphs, greedy, trees

Points, Lines and Ready-made Titles

dfs and similar, dsu, graphs, trees

Policeman and a Tree

dp, graphs, trees

Cities Excursions

dfs and similar, graphs, trees

Mahmoud and Ehab and the bipartiteness

dfs and similar, graphs, trees

Arkady and a Nobody-men

data structures, dfs and similar, trees

Desk Disorder

combinatorics, dfs and similar, dsu, graphs, trees

Third Month Insanity

dp, probabilities, trees

Masha and Cactus

dp, trees

Similar Words

dp, hashing, strings, trees

Harry Vs Voldemort

dfs and similar, dp, graphs, trees

Rowena Ravenclaw's Diadem

trees

Helga Hufflepuff's Cup

dp, trees

Dating

brute force, dfs and similar, graphs, trees

Berland SU Computer Network

constructive algorithms, dfs and similar, graphs, hashing, trees

Chemistry in Berland

dfs and similar, greedy, trees

Upgrading Tree

constructive algorithms, dfs and similar, graphs, math, trees

Nikita and game

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

Ilya And The Tree

dfs and similar, graphs, math, number theory, trees

In a Trap

trees

Journey

dfs and similar, dp, graphs, probabilities, trees

Diverging Directions

data structures, dfs and similar, trees

Roads in the Kingdom

dfs and similar, dp, graphs, trees

Red-Black Cobweb

data structures, divide and conquer, implementation, trees

Misha, Grisha and Underground

dfs and similar, graphs, trees

Perpetual Motion Machine

constructive algorithms, dp, graphs, implementation, math, trees

Singer House

combinatorics, dp, graphs, trees

Best Edge Weight

data structures, dfs and similar, graphs, trees

High Load

constructive algorithms, greedy, implementation, trees