Two Avenues

data structures, dfs and similar, graphs

Long Recovery

constructive algorithms, dfs and similar

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Finding the Vertex

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

Alphabetic Tree

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

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

Rap God

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

Organizing a Music Festival

dfs and similar, math

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

Bus Routes

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

Island Puzzle

dfs and similar, dsu, graphs, trees

Hard Cut

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

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

Chests and Keys

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

Distance Matching

constructive algorithms, dfs and similar, trees

Air Reform

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

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

Just Kingdom

brute force, data structures, dfs and similar

Sloth

dfs and similar, dp, graph matchings, trees

Squid Game

data structures, dfs and similar, greedy, trees

Tree Calendar

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

Archaeology

data structures, dfs and similar, trees

Cycling City

dfs and similar, graphs

Tree and Table

dfs and similar, dp, implementation, trees

Alice and the Cactus

dfs and similar, graphs, math, probabilities

Tree and Permutation Game

dfs and similar, games, graphs, trees

Li Hua and Path

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

Palindromic Hamiltonian Path

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

Edge Queries

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

Berland Miners

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

The Awesomest Vertex

data structures, dfs and similar

Down Below

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

Around the World

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

The Majestic Brown Tree Snake

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

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

A Serious Referee

bitmasks, brute force, dfs and similar, sortings

Falling Sand (Hard Version)

dfs and similar, dp, graphs, greedy

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

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

Cactus Not Enough

dfs and similar, graph matchings, graphs

Wavy numbers

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

Problem of offices

constructive algorithms, dfs and similar, dp, trees

Bitonix' Patrol

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

Bear and Chase

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

TOF

dfs and similar, graphs

Almost Same Distance

dfs and similar, graphs

Snowy Mountain

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

Delete The Edges

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

Omkar and Pies

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

Upgrading Cities

dfs and similar, graphs

Wizards and Bets

dfs and similar, graphs, math, matrices

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

Nikita and game

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

Road Repairs

dfs and similar, graphs, greedy

Matching Reduction

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

Directing Edges

dfs and similar, dp, graphs, trees

Tiles Placement

constructive algorithms, dfs and similar, trees

Pilgrims

dfs and similar, dp, trees

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Two Centroids

data structures, dfs and similar, greedy, trees

Distance to the Path

data structures, dfs and similar, trees

Nezzar and Hidden Permutations

constructive algorithms, dfs and similar, graphs

Rain of Fire

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

Caterpillar

dfs and similar, dp, graphs, trees

Hidden Bipartite Graph

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

Cats on the Upgrade (hard version)

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

Yash And Trees

bitmasks, data structures, dfs and similar, math, number theory

The Red Button

combinatorics, dfs and similar, dsu, graphs, greedy

x-prime Substrings

brute force, dfs and similar, dp, string suffix structures, strings

Checker for Array Shuffling

constructive algorithms, dfs and similar, graphs

Game of Pairs

constructive algorithms, dfs and similar, interactive, math, number theory

Drazil and Morning Exercise

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

e-Government

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

Tree Modification

brute force, constructive algorithms, dfs and similar, graph matchings, graphs, trees

Case of Computer Network

dfs and similar, graphs, trees

Kingdom and its Cities

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

The Meeting Place Cannot Be Changed

dfs and similar, graphs

Baldman and the military

dfs and similar, graphs, trees