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

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Treasure Hunt

graphs, interactive

Inversion Graph

data structures, dsu, graphs, math

Cars

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

Fair Share

constructive algorithms, data structures, dfs and similar, graph matchings, graphs

Spanning Tree Queries

binary search, data structures, dfs and similar, dsu, graphs, greedy, math, sortings, trees

Distance Tree (easy version)

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

Making It Bipartite

flows, graph matchings, graphs, number theory

Not Splitting

geometry, graphs, greedy, implementation, shortest paths

Cats on the Upgrade (hard version)

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

Cats on the Upgrade (easy version)

brute force, data structures, dfs and similar, divide and conquer, dp, graphs, trees

MinOr Tree

bitmasks, dfs and similar, dsu, graphs, greedy

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Christmas Chocolates

dfs and similar, dp, games, graphs, implementation, math, number theory, shortest paths, trees

Just Add an Edge

dfs and similar, dp, graphs

Tricolor Triangles

brute force, graphs, math, matrices

Reindeer Games

binary search, constructive algorithms, data structures, divide and conquer, flows, graphs, shortest paths

Purple Crayon

data structures, dfs and similar, games, graphs, greedy, math, sortings, trees

X(or)-mas Tree

bitmasks, dfs and similar, dsu, graphs, trees

Menorah

brute force, graphs, greedy, math

Crazy Robot

dfs and similar, graphs

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

Social Network

dsu, graphs, greedy, implementation, trees

Dominoes

combinatorics, fft, graphs, math, number theory

Game Master

data structures, dfs and similar, dp, graphs, greedy, two pointers

Robot on the Board 2

brute force, dfs and similar, graphs, implementation

Frog Traveler

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

Desert

data structures, graphs

The Number of Imposters

constructive algorithms, dfs and similar, dp, dsu, graphs

Bakry and Partitioning

bitmasks, constructive algorithms, dfs and similar, dp, graphs, trees

Jumping Through the Array

binary search, data structures, graphs, two pointers

Poachers

dp, games, graphs, trees

Strange LCS

bitmasks, dp, graphs, greedy, strings

Moment of Bloom

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

Diameter of Graph

constructive algorithms, graphs, greedy, math

Railway Construction

brute force, constructive algorithms, data structures, graphs, shortest paths

Array Stabilization (AND version)

brute force, graphs, math, number theory, shortest paths

Productive Meeting

constructive algorithms, graphs, greedy

Kingdom of Islands

brute force, graphs, implementation

Anti-Tetris

constructive algorithms, graphs, shortest paths

Occurrences

combinatorics, dfs and similar, dp, dsu, fft, graphs

The Strongest Build

binary search, brute force, data structures, dfs and similar, graphs, greedy, hashing, implementation

Bridge Club

flows, graph matchings, graphs, greedy

Book

binary search, brute force, data structures, dp, graphs, implementation, sortings

Palindromic Hamiltonian Path

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

One-Four Overload

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

Four Vertices

constructive algorithms, data structures, graphs, greedy, implementation, shortest paths

Mocha and Diana (Hard Version)

brute force, constructive algorithms, dfs and similar, dsu, graphs, greedy, trees, two pointers

Mocha and Diana (Easy Version)

brute force, constructive algorithms, dsu, graphs, greedy, trees

Mocha and Hiking

constructive algorithms, graphs

Down Below

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

DIY Tree

graphs, greedy, math, probabilities

Sports Betting

bitmasks, combinatorics, dp, graphs, math, probabilities

Good Graph

data structures, dsu, graphs, trees

Common Divisor Graph

brute force, constructive algorithms, dsu, graphs, hashing, math, number theory

Permutation Shift

brute force, combinatorics, constructive algorithms, dfs and similar, dsu, graphs, math

Array Differentiation

bitmasks, brute force, constructive algorithms, dfs and similar, dp, graphs, math

Running for Gold

combinatorics, graphs, greedy, sortings

Jumping Around

binary search, data structures, divide and conquer, dp, dsu, graphs, shortest paths

Gregor and the Pawn Game

dfs and similar, dp, flows, graph matchings, graphs, greedy, implementation

Gregor and the Two Painters

data structures, divide and conquer, graphs, greedy, math

Web of Lies

brute force, graphs, greedy

How Many Paths?

dfs and similar, dp, graphs, trees

AquaMoon and Permutations

2-sat, brute force, combinatorics, constructive algorithms, graph matchings, graphs

The Final Pursuit

bitmasks, constructive algorithms, divide and conquer, graphs, greedy, math

Tree Array

brute force, combinatorics, dp, graphs, math, probabilities, trees

Great Graphs

constructive algorithms, graphs, greedy, shortest paths, sortings