The Third Letter

dfs and similar, dsu, graphs, greedy, implementation

The Boss's Identity

binary search, bitmasks, data structures, dfs and similar, greedy, math, sortings

Tree Weights

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

Great Grids

2-sat, constructive algorithms, dfs and similar, dsu, graphs

Omsk Metro (hard version)

data structures, dfs and similar, divide and conquer, dp, math, trees

Omsk Metro (simple version)

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

Apple Tree

combinatorics, dfs and similar, dp, math, trees

Tenzing and Tree

dfs and similar, greedy, shortest paths, sortings, trees

Railguns

brute force, dfs and similar, dp, graphs

Decreasing Game

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

Good Graph

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

Doctor's Brown Hypothesis

dfs and similar, graphs, math, number theory

Ksyusha and Chinchilla

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

Round Dance

dfs and similar, dsu, graphs, shortest paths

Copil Copac Draws Trees

dfs and similar, dp, graphs, trees

Forever Winter

dfs and similar, graphs, math

The Lakes

dfs and similar, dsu, graphs, implementation

Gold Rush

brute force, dfs and similar, dp, implementation

Bus Routes

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

Two Centroids

data structures, dfs and similar, greedy, trees

LuoTianyi and XOR-Tree

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

LuoTianyi and the Floating Islands (Hard Version)

combinatorics, dfs and similar, math, probabilities, trees

Gardening Friends

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

Fish Graph

brute force, constructive algorithms, dfs and similar, graphs

Between

constructive algorithms, dfs and similar, graphs, greedy

Is It Flower?

dfs and similar, graphs, implementation

Monsters

brute force, data structures, dfs and similar, dsu, graphs, greedy

Bouncy Ball

brute force, dfs and similar, implementation

Tree Master

brute force, data structures, dfs and similar, trees

There Should Be a Lot of Maximums

brute force, data structures, dfs and similar, dp, trees, two pointers

A Wide, Wide Graph

dfs and similar, dp, graphs, greedy, trees

Routing

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

Symmetree

dfs and similar, hashing, implementation, trees

Unforgivable Curse (hard version)

brute force, constructive algorithms, dfs and similar, dsu, graphs, greedy, strings

Tree Cutting

bitmasks, dfs and similar, dp

City Union

constructive algorithms, dfs and similar, dsu, geometry, greedy, implementation, math

Li Hua and Path

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

Li Hua and Tree

brute force, data structures, dfs and similar, dp, implementation, trees

Colored Subgraphs

dfs and similar, dp, games, greedy, trees

Removal Sequences

bitmasks, dfs and similar, graphs

Blocking Chips

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

Divisors and Table

brute force, dfs and similar, dp, number theory

Tokens on Graph

constructive algorithms, dfs and similar, graphs, shortest paths

Timofey and Black-White Tree

brute force, dfs and similar, divide and conquer, graphs, greedy, math, shortest paths, trees

XOR, Tree, and Queries

bitmasks, constructive algorithms, dfs and similar, dsu, graphs, greedy, implementation, trees

Sum Over Zero

data structures, dfs and similar, dp

Game on Axis

combinatorics, dfs and similar, dsu, graphs, implementation

Double Sort II

dfs and similar, flows, graph matchings, graphs

Maximizing Root

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

The Tree Has Fallen!

bitmasks, dfs and similar, math, trees

Edge Reverse

binary search, dfs and similar, graphs, trees

Score of a Tree

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

Friendly Spiders

dfs and similar, graphs, math, number theory, shortest paths

Two Chess Pieces

dfs and similar, dp, greedy, trees

Copy of a Copy of a Copy

constructive algorithms, dfs and similar, graphs, implementation, sortings

Hossam and (sub-)palindromic tree

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

Koxia and Tree

combinatorics, dfs and similar, dp, dsu, math, probabilities, trees

Koxia and Game

constructive algorithms, data structures, dfs and similar, dsu, flows, games, graph matchings, graphs, implementation

Lucky Permutation

constructive algorithms, dfs and similar, graphs, greedy

Doremy's Experimental Tree

brute force, constructive algorithms, dfs and similar, dsu, sortings, trees

Edge Queries

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

Set Construction

constructive algorithms, dfs and similar, graphs, greedy

SlavicG's Favorite Problem

bitmasks, dfs and similar, graphs

Tick, Tock

combinatorics, dfs and similar, dsu, graphs

The Beach

constructive algorithms, dfs and similar, graphs, shortest paths

Distance to the Path

data structures, dfs and similar, trees

Cactus Wall

constructive algorithms, dfs and similar, graphs, shortest paths

Paths on the Tree

dfs and similar, dp, greedy, sortings, trees

Kirill and Company

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

Masha and a Beautiful Tree

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

Hanging Hearts

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

Reset K Edges

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

Permutation Addicts

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

Phase Shift

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

Edge Split

brute force, constructive algorithms, dfs and similar, dsu, graphs, probabilities, trees

L-shapes

dfs and similar, implementation

Matching Reduction

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

Prefix Function Queries

dfs and similar, dp, hashing, string suffix structures, strings, trees

Maximum AND

bitmasks, dfs and similar, divide and conquer, greedy, sortings

Swap and Maximum Block

bitmasks, data structures, dfs and similar, divide and conquer, dp

Path Prefixes

binary search, data structures, dfs and similar, trees

Triameter

binary search, data structures, dfs and similar, trees

XOR Tree

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

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

DFS Trees

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

Qpwoeirut and Vertices

binary search, data structures, dfs and similar, divide and conquer, dsu, greedy, trees

Passable Paths (hard version)

data structures, dfs and similar, trees

Passable Paths (easy version)

dfs and similar, trees

Split Into Two Sets

dfs and similar, dsu, graphs

Tree Recovery

brute force, constructive algorithms, dfs and similar, dsu, graphs, trees

Ambiguous Dominoes

constructive algorithms, dfs and similar, graphs

Tree Queries (Hard Version)

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

Tree Queries (Easy Version)

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

Fake Plastic Trees

dfs and similar, dp, greedy, trees

K-Set Tree

combinatorics, dfs and similar, dp, math, trees

Number of Groups

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

ANDfinity

bitmasks, brute force, constructive algorithms, dfs and similar, dsu, graphs

Infected Tree

dfs and similar, dp, trees

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Hard Cut

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