Li Hua and Maze

constructive algorithms, flows, graphs, greedy, implementation

Removal Sequences

bitmasks, dfs and similar, graphs

Graph Coloring (hard version)

brute force, combinatorics, divide and conquer, dp, fft, graphs

Graph Coloring (easy version)

combinatorics, dp, graphs

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

Game on Axis

combinatorics, dfs and similar, dsu, graphs, implementation

Double Sort II

dfs and similar, flows, graph matchings, graphs

The Game of the Century

constructive algorithms, graphs, shortest paths

Anya's Simultaneous Exhibition

constructive algorithms, graphs, greedy, interactive, sortings

Maximizing Root

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

Edge Reverse

binary search, dfs and similar, graphs, trees

Italian Data Centers

graphs, shortest paths

Train Splitting

constructive algorithms, graphs, greedy

Friendly Spiders

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

Copy of a Copy of a Copy

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

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

Algebra Flash

bitmasks, brute force, dp, graphs, math, meet-in-the-middle, trees

Hospital Queue

binary search, graphs, greedy, implementation

Doremy's City Construction

graphs, greedy

Edge Queries

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

Node Pairs

dp, graphs, math, number theory

Make It Connected

binary search, brute force, constructive algorithms, dsu, graphs, greedy, matrices, trees, two pointers

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

Cactus Wall

constructive algorithms, dfs and similar, graphs, shortest paths

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

Arranging Crystal Balls

data structures, divide and conquer, divide and conquer, dp, geometry, graphs, number theory

Reset K Edges

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

Connectivity Addicts

constructive algorithms, dsu, graphs, greedy, interactive, shortest paths, trees

Permutation Addicts

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

Ela and the Wiring Wizard

brute force, dp, graphs, greedy, implementation, shortest paths

Phase Shift

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

Edge Split

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

Jatayu's Balanced Bracket Sequence

data structures, dsu, graphs, greedy

Moving Both Hands

dp, graphs, shortest paths

Matching Reduction

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

Impressionism

constructive algorithms, graphs, implementation, math

Madoka and The First Session

constructive algorithms, flows, graph matchings, graphs, implementation

Long Way Home

data structures, divide and conquer, dp, geometry, graphs, greedy, shortest paths

2+ doors

2-sat, bitmasks, graphs, greedy

Party

brute force, graphs

Multiset of Strings

bitmasks, brute force, dp, fft, flows, graphs, math, meet-in-the-middle, trees

DFS Trees

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

Count Seconds

brute force, constructive algorithms, dp, graphs, implementation, math

Split Into Two Sets

dfs and similar, dsu, graphs

Equal Reversal

constructive algorithms, graphs, implementation, math

Too Many Constraints

2-sat, constructive algorithms, graphs, implementation

Coloring

brute force, combinatorics, constructive algorithms, dp, geometry, graphs, greedy, implementation, math

Tree Recovery

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

Ambiguous Dominoes

constructive algorithms, dfs and similar, graphs

Zero Path

brute force, data structures, dp, graphs, greedy, shortest paths

Keshi in Search of AmShZ

graphs, greedy, shortest paths

Number of Groups

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

Shifting String

graphs, math, number theory, strings

ANDfinity

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

Railway System

constructive algorithms, graphs, greedy, interactive, sortings

MCMF?

data structures, flows, graphs, greedy, sortings, two pointers

Unordered Swaps

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

Lenient Vertex Cover

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

Toss a Coin to Your Graph...

binary search, dfs and similar, dp, graphs

Tokitsukaze and Two Colorful Tapes

constructive algorithms, dfs and similar, graphs, greedy

White-Black Balanced Subtrees

dfs and similar, dp, graphs, trees

Vertical Paths

graphs, implementation, trees

Remove Directed Edges

dfs and similar, dp, graphs

Cross Xor

constructive algorithms, graphs, math, matrices

Checker for Array Shuffling

constructive algorithms, dfs and similar, graphs

Array Shuffling

constructive algorithms, graphs, greedy

Where is the Pizza?

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

Labyrinth

dfs and similar, graphs

Circular Maze

brute force, dfs and similar, graphs, implementation

Training Camp

flows, graphs

Antennas

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

European Trip

dp, graphs, math, matrices

Getting Zero

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

Tree and Permutation Game

dfs and similar, games, graphs, trees

AND-MEX Walk

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

Words on Tree

2-sat, dfs and similar, dsu, graphs, trees

Neighbour Ordering

constructive algorithms, graphs

Cycle Palindrome

constructive algorithms, graphs, math

Parametric MST

binary search, constructive algorithms, graphs, greedy, math, sortings

Snowy Mountain

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

Arithmetic Operations

brute force, data structures, graphs, math

Nearest Excluded Points

binary search, data structures, dfs and similar, graphs, shortest paths

Counting Shortcuts

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

Two Avenues

data structures, dfs and similar, graphs

Air Reform

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

Madoka and the Elegant Gift

brute force, constructive algorithms, graphs, implementation

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive