Message Transmission Error (hard version)

hashing, string suffix structures, strings, two pointers

Yunli's Subarray Queries (extreme version)

data structures, dp, implementation

Yunli's Subarray Queries (hard version)

binary search, data structures, dp

Yunli's Subarray Queries (easy version)

binary search, data structures, two pointers

Firefly's Queries

bitmasks, data structures, flows, math

Sakurako's Test

binary search, brute force, greedy, math, number theory

Sakurako's Task

binary search, greedy, math, number theory

Dora's Paint

brute force, combinatorics, constructive algorithms, graphs, implementation

Iris's Full Binary Tree

brute force, data structures, dfs and similar, trees

Iris and Adjacent Products

data structures, greedy, implementation, math

Eri and Expanded Sets

data structures, divide and conquer, math, number theory, two pointers

Iris and the Tree

brute force, data structures, dfs and similar, dsu, math, trees

Iris and Game on the Tree

constructive algorithms, dfs and similar, games, graphs, greedy, trees

Substring Compression

data structures, dp, matrices

Make a Palindrome

binary search, brute force, data structures, greedy, math

Not a Nim Problem

brute force, games, math, number theory

Colored Portals

binary search, brute force, data structures, graphs, greedy, implementation, shortest paths

Turtle and Three Sequences

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

Turtle and Inversions (Hard Version)

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

Turtle and Inversions (Easy Version)

brute force, divide and conquer, dp, greedy, math

Turtle and a MEX Problem (Hard Version)

dfs and similar, dp, graphs, greedy, implementation, math

Counting 101

greedy

Lattice Optimizing

bitmasks, brute force, hashing, meet-in-the-middle

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

DFS Checker (Hard Version)

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

DFS Checker (Easy Version)

brute force, data structures, dfs and similar, graphs, hashing, trees

Deterministic Heap (Hard Version)

combinatorics, dp, trees

Deterministic Heap (Easy Version)

combinatorics, dp, math, trees

Longest Max Min Subsequence

brute force, constructive algorithms, data structures, greedy, implementation

Ksyusha and the Loaded Set

binary search, brute force, data structures, implementation

Call During the Journey

binary search, brute force, graphs, greedy, shortest paths

Color Rows and Columns

dp, greedy, implementation, math

Ruler (hard version)

binary search, interactive, ternary search

Eliminating Balls With Merging (Hard Version)

binary search, brute force, data structures, divide and conquer, greedy, implementation

Eliminating Balls With Merging (Easy Version)

binary search, brute force, data structures, divide and conquer, greedy

Determine Winning Islands in Race

data structures, dp, graphs, greedy, shortest paths

Perform Operations to Maximize Score

binary search, brute force, constructive algorithms, greedy, implementation

Chips on a Line

brute force, combinatorics, dp, greedy, math

Level Up

binary search, brute force, data structures, divide and conquer, implementation

Penacony

brute force, data structures, graphs, greedy, hashing

Bomb

binary search, greedy, math

Decode

combinatorics, data structures, implementation, 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

Squaring

brute force, constructive algorithms, greedy, implementation, math, number theory

Bouquet (Hard Version)

binary search, data structures, greedy, math, sortings, two pointers

Fortnite

combinatorics, constructive algorithms, games, greedy, hashing, interactive, math, number theory, strings

Minecraft

bitmasks, brute force, dp, graphs, math

Stardew Valley

constructive algorithms, dfs and similar, graphs, trees

Wooden Game

bitmasks, greedy, math, trees

Funny Game

constructive algorithms, dsu, graphs, greedy, math, number theory, trees

Hungry Games

binary search, dp, two pointers

Dyn-scripted Robot (Hard Version)

chinese remainder theorem, math, number theory

Dyn-scripted Robot (Easy Version)

brute force, chinese remainder theorem, constructive algorithms, math, number theory

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

Novice's Mistake

brute force, constructive algorithms, implementation, math, strings

Grid Game

constructive algorithms, games, graph matchings, greedy, interactive

Prime Split Game

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

Grid Reset

constructive algorithms, greedy, implementation

Triangle Formation

brute force, greedy, implementation, math, sortings

Coloring Game

constructive algorithms, dfs and similar, games, graphs, greedy, interactive

Prime XOR Coloring

bitmasks, constructive algorithms, graphs, greedy, math, number theory

Polygonal Segments

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

Catch the Mole(Hard Version)

binary search, data structures, dfs and similar, divide and conquer, interactive, trees

Catch the Mole(Easy Version)

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

Grid Puzzle

bitmasks, brute force, dp, greedy, implementation

Simultaneous Coloring

dfs and similar, divide and conquer, graphs

Distance to Different

combinatorics, dp, math

Smithing Skill

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

Heartbeat

combinatorics, dp, fft, math

Range Minimum Sum

binary search, brute force, data structures, divide and conquer, implementation

The Omnipotent Monster Killer

brute force, dfs and similar, dp, trees

Fumo Temple

interactive

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

Wonderful Tree!

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

World is Mine

dp, games

Permutation Problem (Hard Version)

brute force, data structures, hashing, math, number theory

Permutation Problem (Simple Version)

binary search, brute force, combinatorics, data structures, math, number theory

Non-academic Problem

dfs and similar, graphs, trees

Beautiful Array

greedy, math, number theory, sortings

Maximize the Largest Component (Hard Version)

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

Maximize the Largest Component (Easy Version)

brute force, data structures, dfs and similar, dsu, graphs, implementation

D-Function

combinatorics, math, number theory

Tower Capturing

combinatorics, dp, geometry

Magic Trick II

constructive algorithms, implementation, sortings

Reconstruction

brute force, dp, math

Shuffle

dp, greedy, trees

''a'' String Problem

brute force, hashing, implementation, math, string suffix structures, strings

Magnitude (Hard Version)

combinatorics, dp, greedy, math

Your Loss

bitmasks, brute force, dp, trees

array-value

binary search, bitmasks, data structures, greedy, two pointers