The Ultimate LIS Problem

data structures, greedy

Permutation Weight (Hard Version)

constructive algorithms, greedy

Permutation Weight (Easy Version)

constructive algorithms, dfs and similar, dsu

Bring Balance

brute force, constructive algorithms, greedy

Hard Cut

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

Euclid Guess

constructive algorithms, flows, graph matchings, math, number theory

Diverse Segments

data structures, two pointers

MCMF?

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

Unordered Swaps

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

Labyrinth Adventures

data structures, dp, matrices, shortest paths

Lenient Vertex Cover

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

Dog Walking

brute force, greedy, math

Formalism for Formalism

bitmasks, dp, math

Typical Party in Dorm

bitmasks, combinatorics, dp, strings

Tokitsukaze and Gems

dp, math

Tokitsukaze and Beautiful Subsegments

data structures

Tokitsukaze and Permutations

dp, math

Anti-Theft Road Planning

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

Power or XOR?

bitmasks, combinatorics, math, number theory

PermutationForces

data structures, greedy

Zigu Zagu

constructive algorithms, data structures, greedy

Cross Xor

constructive algorithms, graphs, math, matrices

Checker for Array Shuffling

constructive algorithms, dfs and similar, graphs

Permutation Counting

brute force, combinatorics, dp, fft, math

Jee, You See?

bitmasks, combinatorics, dp

Yin Yang

implementation

Centroid Probabilities

combinatorics, dp, fft, math

Edge Elimination

constructive algorithms, dfs and similar, dp, trees

Half Queen Cover

constructive algorithms, math

Kingdom Partition

flows

Heroes of Might

math

Global Warming

geometry, math

Even Split

binary search, constructive algorithms, greedy, math

Budget Distribution

Admissible Map

MinimizOR

bitmasks, brute force, data structures, divide and conquer, greedy, implementation, two pointers

Teleporters

binary search, greedy

Narrow Components

brute force, data structures, dp, dsu, math, trees

Tree and Permutation Game

dfs and similar, games, graphs, trees

Juju and Binary String

brute force, constructive algorithms, greedy, math

Gojou and Matrix Game

data structures, dp, games, hashing, implementation, math, number theory, sortings

Words on Tree

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

Neighbour Ordering

constructive algorithms, graphs

Equal LCM Subsets

data structures, math, number theory

Cycle Palindrome

constructive algorithms, graphs, math

Parametric MST

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

Three Minimums

combinatorics, constructive algorithms, divide and conquer, dp, fft, math

Snowy Mountain

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

Minimal String Xoration

bitmasks, data structures, divide and conquer, greedy, hashing, sortings, strings

Tower Defense

binary search, brute force, data structures

Sum of Matchings

brute force, combinatorics, constructive algorithms, dfs and similar, graph matchings, greedy, math

Two Avenues

data structures, dfs and similar, graphs

Air Reform

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

Serious Business

data structures, divide and conquer, dp, implementation, shortest paths

Madoka and Laziness

dp, greedy

Madoka and the Sixth-graders

data structures, dfs and similar, greedy

Playing Around the Table

constructive algorithms, greedy, implementation

Basis

combinatorics, fft, math, number theory

Covering Circle

geometry

Special Positions

combinatorics, divide and conquer, fft, math

Two Arrays

bitmasks, brute force, combinatorics, greedy, hashing, math, two pointers

Two Posters

brute force, data structures, greedy, two pointers

Colorful Operations

brute force, data structures, implementation

Minimize Inversions Number

data structures, greedy, math, sortings

Birthday

constructive algorithms, greedy, math

Towers

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

Closest Pair

data structures, greedy

Fibonacci Additions

brute force, data structures, hashing, implementation, math

Fair Share

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

Perfect Matching

data structures, divide and conquer, interactive, trees

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

Making It Bipartite

flows, graph matchings, graphs, number theory

Expected Components

combinatorics, math, number theory, probabilities

Flipping Range

constructive algorithms, dp, greedy, number theory

Spaceship Crisis Management

binary search, data structures, geometry, sortings

Groceries in Meteor Town

binary search, data structures, dsu, trees

Game on Sum (Hard Version)

combinatorics, dp, games, math

Not Splitting

geometry, graphs, greedy, implementation, shortest paths

A Random Code Problem

combinatorics, dp, math, number theory, probabilities

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

Middle Duplication

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

Quadratic Set

constructive algorithms, hashing, math, number theory

Two Sequences

data structures, hashing, string suffix structures

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Weighted Increasing Subsequences

data structures, dp, math

Strange Instructions

data structures, greedy, implementation

Subsequences Galore

bitmasks, combinatorics, dp

Bipartite Array

dp, greedy

Permutation and Queries

brute force, data structures, divide and conquer, two pointers

Christmas Chocolates

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

Too Many Impostors (hard version)

constructive algorithms, implementation, interactive, math

Keep XOR Low

bitmasks, combinatorics, data structures, divide and conquer, dp, math

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

Maximum Adjacent Pairs

constructive algorithms, graph matchings