Substring Compression

data structures, dp, matrices

Court Blue (Hard Version)

brute force, dp, math, number theory

Court Blue (Easy Version)

brute force, dfs and similar, dp, math, number theory

Cosmic Rays

brute force, data structures, dp

Deterministic Heap (Hard Version)

combinatorics, data structures, dp, trees

Deterministic Heap (Easy Version)

combinatorics, dp, math, trees

Color Rows and Columns

dp, greedy, implementation, math

Determine Winning Islands in Race

data structures, dp, graphs, greedy, shortest paths

Chips on a Line

brute force, combinatorics, dp, greedy, math

Let Me Teach You a Lesson (Hard Version)

data structures, dp, matrices, two pointers

Let Me Teach You a Lesson (Easy Version)

2-sat, data structures, dp, matrices, two pointers

Cases

bitmasks, brute force, dp, strings

Minecraft

bitmasks, brute force, dp, graphs, math

Xor-Grid Problem

bitmasks, constructive algorithms, dp, implementation

Med-imize

binary search, dp, greedy

Ultra-Meow

combinatorics, dp, math

Valuable Cards

brute force, dp, greedy, number theory, two pointers

Prime Split Game

bitmasks, dp, fft, games, math, number theory

Polygonal Segments

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

Grid Puzzle

bitmasks, brute force, dp, greedy, implementation

Distance to Different

combinatorics, dp, math

Smithing Skill

brute force, data structures, dp, greedy, math, sortings, two pointers

Heartbeat

combinatorics, dp, fft, math

The Omnipotent Monster Killer

brute force, dfs and similar, dp, trees

Spinning Round (Hard Version)

divide and conquer, dp, trees

Spinning Round (Easy Version)

divide and conquer, dp, trees

Interesting Problem (Hard Version)

dp

Interesting Problem (Easy Version)

dp

World is Mine

dp, games

Maximize the Largest Component (Hard Version)

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

Tower Capturing

combinatorics, dp, geometry

Reconstruction

brute force, dp, math

Shuffle

dp, greedy, trees

Your Loss

bitmasks, brute force, dp, trees

Number of k-good subarrays

bitmasks, brute force, combinatorics, divide and conquer, dp, math, meet-in-the-middle

Turtle and Paths on a Tree

data structures, dp, trees

Fixing a Binary String

bitmasks, brute force, constructive algorithms, dp, greedy, hashing, strings

Computing Machine

brute force, data structures, dp, greedy, implementation

Nikita and LCM

brute force, data structures, dp, greedy, math, number theory, sortings

Remove Bridges

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

Mind Bloom

dp

Set

bitmasks, brute force, combinatorics, dfs and similar, divide and conquer, dp, math

Money Buys Happiness

dp

Maximum GCD Sum Queries

bitmasks, brute force, dp, implementation, number theory

Min-Fund Prison (Hard)

bitmasks, dfs and similar, dp, graphs, trees

Min-Fund Prison (Medium)

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

Trails (Hard)

dp, matrices

Trails (Medium)

dp, matrices

Trails (Easy)

dp

Game on Tree (Hard)

dfs and similar, dp, games, trees

Card Pairing

dp, greedy, hashing, implementation

Unique Array

binary search, data structures, divide and conquer, dp, greedy

Division + LCP (hard version)

binary search, brute force, data structures, dp, hashing, math, string suffix structures, strings

Division + LCP (easy version)

binary search, data structures, dp, hashing, string suffix structures, strings

Again Counting Arrays (Hard Version)

combinatorics, dp, math

Again Counting Arrays (Easy Version)

combinatorics, dp, fft, math

Fenwick Tree

bitmasks, brute force, combinatorics, data structures, dp, math, trees

Composite Spells

*special problem, dp

Carousel of Combinations

brute force, combinatorics, dp, math, number theory

A BIT of an Inequality

bitmasks, brute force, dp, math

Nene and the Mex Operator

bitmasks, brute force, constructive algorithms, divide and conquer, dp, greedy, implementation, math

The Most Reckless Defense

bitmasks, brute force, constructive algorithms, dp, flows, graph matchings, shortest paths

GCD on a grid

brute force, dfs and similar, dp, implementation, math, number theory

Unfair Game

dp, games, greedy, math, schedules

Unique Strings

combinatorics, dp, math

Colored Balls

combinatorics, dp, math, sortings

Thanos Snap

binary search, dp, games, greedy, trees

Shuffling Songs

bitmasks, dfs and similar, dp, graphs, hashing, implementation, strings

Annual Ants' Gathering

dfs and similar, dp, greedy, trees

Grove

brute force, dfs and similar, dp, geometry, probabilities

Nobody is needed

2-sat, data structures, dfs and similar, dp

Girl Permutation

combinatorics, dp, math, number theory

Minimum Hamming Distance

dp

Counting Is Fun (Hard Version)

combinatorics, dp

Counting Is Fun (Easy Version)

brute force, combinatorics, dp, math

Farmer John's Favorite Intern

data structures, dp, flows, trees

Bessie and Cards

combinatorics, dp, math

Learning to Paint

binary search, data structures, dfs and similar, dp, greedy, implementation, sortings

Messenger in MAC

binary search, brute force, constructive algorithms, data structures, dp, greedy, sortings

Turtle Mission: Robot and the Earthquake

dfs and similar, dp, graphs, shortest paths

Feed Cats

data structures, dp, sortings

Prefix Max Set Counting

data structures, dp, trees

2..3...4.... Wonderful! Wonderful!

combinatorics, dp, math

Sum over all Substrings (Hard Version)

bitmasks, divide and conquer, dp, dsu, greedy, implementation, strings

Sum over all Substrings (Easy Version)

brute force, dp, greedy, strings

Sasha and the Happy Tree Cutting

bitmasks, brute force, dfs and similar, dp, graphs, greedy, math, trees

Sasha and a Walk in the City

combinatorics, dp, math, trees

Modular Sequence

brute force, constructive algorithms, dp, graphs, greedy, math, number theory

Paint Charges

data structures, dp, greedy, math

Vlad and Trouble at MIT

dfs and similar, dp, flows, graphs, greedy, implementation, trees

Vlad and Avoiding X

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

Good Trip

combinatorics, dp, math, probabilities

Anti-Proxy Attendance

constructive algorithms, dp, interactive, ternary search

Balanced Subsequences

combinatorics, dp, math

Count Paths

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

Replace on Segment

dp, graph matchings

Mischievous Shooter

brute force, data structures, divide and conquer, dp, implementation

Sum of Progression

brute force, data structures, dp, implementation, math

Counting Binary Strings

combinatorics, dp, math

Wine Factory (Hard Version)

data structures, dp, flows, greedy, matrices