White-Black Balanced Subtrees

dfs and similar, dp, graphs, trees

Vlad and Unfinished Business

dfs and similar, dp, greedy, trees

Remove Directed Edges

dfs and similar, dp, graphs

Checker for Array Shuffling

constructive algorithms, dfs and similar, graphs

Hemose on the Tree

bitmasks, constructive algorithms, dfs and similar, trees

Where is the Pizza?

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

Fall Down

dfs and similar, implementation

Edge Elimination

constructive algorithms, dfs and similar, dp, trees

Labyrinth

dfs and similar, graphs

Circular Maze

brute force, dfs and similar, graphs, implementation

Antennas

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

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

Equal Tree Sums

constructive algorithms, dfs and similar, math, trees

Snowy Mountain

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

Potion Brewing Class

dfs and similar, math, number theory, trees

Sum of Matchings

brute force, combinatorics, constructive algorithms, dfs and similar, graph matchings, greedy, 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 Sixth-graders

data structures, dfs and similar, greedy

Weight the Tree

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

Towers

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

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 (hard version)

binary search, dfs and similar, shortest paths, trees

Distance Tree (easy version)

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

Not Assigning

constructive algorithms, dfs and similar, number theory, trees

Black and White Tree

dfs and similar, greedy, trees

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

Middle Duplication

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

Game on Ranges

brute force, dfs and similar, implementation, sortings

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Hidden Permutations

dfs and similar, interactive, math

Unusual Minesweeper

binary search, dfs and similar, dsu, greedy, sortings

Reverse

bitmasks, constructive algorithms, dfs and similar, implementation, math, strings

Christmas Chocolates

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

Just Add an Edge

dfs and similar, dp, graphs

Purple Crayon

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

X(or)-mas Tree

bitmasks, dfs and similar, dsu, graphs, trees

Crazy Robot

dfs and similar, graphs

Escape The Maze (hard version)

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

Escape The Maze (easy version)

dfs and similar, greedy, shortest paths, trees, two pointers

Squid Game

data structures, dfs and similar, greedy, trees

Mashtali: a Space Oddysey

constructive algorithms, dfs and similar, graphs

Alphabetic Tree

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

Game Master

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

Robot on the Board 2

brute force, dfs and similar, graphs, implementation

Treelabeling

bitmasks, constructive algorithms, dfs and similar, games, greedy, implementation, trees

Two Sorts

binary search, dfs and similar, math, meet-in-the-middle

Frog Traveler

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

Robot Factory

bitmasks, dfs and similar

Staircases

brute force, combinatorics, data structures, dfs and similar, dp, implementation, math

Computer Game

brute force, dfs and similar, dp, implementation

The Number of Imposters

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

Red-Black Number

dfs and similar, dp, implementation, math, meet-in-the-middle

Gardener and Tree

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

Make it Divisible by 25

dfs and similar, dp, greedy, math, math

Hemose in ICPC ?

binary search, dfs and similar, implementation, interactive, math, number theory, trees

Bakry and Partitioning

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

Frequency Queries

data structures, dfs and similar, trees

Moment of Bloom

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

Just Kingdom

brute force, data structures, dfs and similar

Divisible by Twenty-Five

brute force, dfs and similar, dp

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

Palindromic Hamiltonian Path

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

One-Four Overload

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

Buds Re-hanging

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

Nearest Beautiful Number (hard version)

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

Nearest Beautiful Number (easy version)

binary search, bitmasks, brute force, constructive algorithms, dfs and similar, greedy

Mocha and Diana (Hard Version)

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

Down Below

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

You

dfs and similar, dp, math, number theory

Permutation Shift

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

Organizing a Music Festival

dfs and similar, math

A Serious Referee

bitmasks, brute force, dfs and similar, sortings

Array Differentiation

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

Equidistant Vertices

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

Gregor and the Pawn Game

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

How Many Paths?

dfs and similar, dp, graphs, trees

Need for Pink Slips

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

Figure Fixing

constructive algorithms, dfs and similar, dsu, graphs, greedy, math

Playoff Tournament

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

Falling Sand (Hard Version)

dfs and similar, dp, graphs, greedy

Falling Sand (Easy Version)

dfs and similar, graphs, greedy

Excursions

*special problem, constructive algorithms, dfs and similar, flows, graph matchings, graphs

Biome Map

*special problem, constructive algorithms, dfs and similar, graphs

Trees of Tranquillity

data structures, dfs and similar, greedy, trees

Parsa's Humongous Tree

dfs and similar, divide and conquer, dp, greedy, trees

MEX Tree

combinatorics, dfs and similar, implementation, math, trees

Nastia Plays with a Tree

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

To Go Or Not To Go?

brute force, dfs and similar, graphs, greedy, implementation, shortest paths

Chests and Keys

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