Robin Helps

greedy, implementation

Game in Tree (Hard Version)

binary search, data structures, trees

Game in Tree (Easy Version)

binary search, brute force, data structures, dp, games, greedy, implementation, trees

Prefix GCD

brute force, dp, greedy, math, number theory

Minimize the Difference

binary search, greedy

Password Cracking

constructive algorithms, interactive, strings

Battle for Survive

constructive algorithms, greedy, math

Zhan's Blender

constructive algorithms, math

Stack and Queue

*special problem, data structures, divide and conquer

Strange Matrix

*special problem, graphs, greedy

Removal of a Permutation

*special problem

Good Subarray

*special problem, data structures, greedy

Rock-Paper-Scissors Bot

*special problem, greedy, strings

Among Wolves

*special problem

Split the Expression

*special problem

Shuffle

*special problem

Problem Solving

*special problem

Message Transmission Error (hard version)

hashing, string suffix structures, strings, two pointers

Message Transmission Error (easy version)

brute force, strings

Three Brothers

brute force, implementation, math

Alternating Sum of Numbers

brute force, implementation, math

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

Klee's SUPER DUPER LARGE Array!!!

binary search, math, ternary search

Satyam and Counting

geometry, math

The Legend of Freya the Frog

implementation, math

osu!mania

brute force, implementation

Minimize!

brute force, math

Sakurako's Test

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

Sakurako's Task

binary search, greedy, math, number theory

Sakurako's Box

combinatorics, math, number theory

Alternating String

brute force, data structures, dp, greedy, implementation, strings

Sakurako's Hobby

dp, dsu, graphs, math

Longest Good Array

binary search, brute force, math

Square or Not

brute force, math, strings

Sakurako's Exam

brute force, constructive algorithms, greedy, math

Dora and C++

math, number theory

Index and Maximum Value

data structures, greedy

Dora's Set

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

Subtangle Game (Hard Version)

data structures, dp, games, greedy, implementation

Subtangle Game (Easy Version)

dp, games, greedy, implementation

Alter the GCD

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

Lazy Narek

dp, implementation, strings

The Strict Teacher (Hard Version)

binary search, greedy, math, sortings

The Strict Teacher (Easy Version)

greedy, math, sortings

Simple Palindrome

combinatorics, constructive algorithms, greedy, math

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

Splitting Items

games, greedy, sortings

Game with Doors

brute force, greedy

Closest Point

implementation, math

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

Turtle and a MEX Problem (Easy Version)

greedy, math

Turtle and Good Pairs

constructive algorithms, greedy, sortings, strings

Turtle and Piggy Are Playing a Game 2

games, greedy, sortings

Turtle and Good Strings

greedy, strings

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

Black Circles

brute force, geometry, greedy, math

Removals Game

constructive algorithms, games

Distanced Coloring

constructive algorithms, implementation, math

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

Guess The Tree

binary search, brute force, dfs and similar, divide and conquer, dsu, greedy, interactive, trees

Generate Permutation

constructive algorithms

Make All Equal

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

Photoshoot for Gorillas

combinatorics, data structures, greedy, math

Right Left Wrong

greedy, implementation, two pointers

Numeric String Template

data structures, strings

Seating in a Bus

two pointers

Primary Task

implementation, math, strings

Ruler (hard version)

binary search, interactive, ternary search

Ruler (easy version)

binary search, interactive

Expected Median

combinatorics, math

Triple Operations

dp, implementation, math

Slavic's Exam

greedy, implementation, strings

Showering

greedy, implementation

Card Game

brute force, constructive algorithms, implementation