Simultaneous Coloring

dfs and similar, divide and conquer, graphs

Turtle and Paths on a Tree

data structures, dp, trees

Kostyanych's Theorem

brute force, constructive algorithms, graphs, interactive

Remove Bridges

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

Zimpha Fan Club

fft, greedy, math, strings

Card Pairing

dp, greedy, hashing, implementation

Long Way to be Non-decreasing

binary search, dfs and similar, graphs, implementation, shortest paths, two pointers

Missing Subarray Sum

constructive algorithms

Nene and the Passing Game

constructive algorithms, data structures, dsu, graphs, sortings

Make Triangle

constructive algorithms, math

Damage per Second

brute force, math

MEX Game 2 (Easy Version)

binary search, brute force, greedy

Counting Is Fun (Hard Version)

combinatorics, dp

Bessie and Cards

combinatorics, dp, math

XOR Operations

Symmetric Boundary

Attraction Score

Andrey's Tree

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

Weird LCM Operations

brute force, constructive algorithms, number theory

Digital Patterns

combinatorics, data structures, implementation, math

Shrink-Reverse

binary search, brute force, greedy, hashing, implementation, string suffix structures, strings

Smooth Sailing (Hard Version)

binary search, data structures, dsu, geometry, graphs, trees

Wine Factory (Hard Version)

data structures, dp, flows, greedy, matrices

Group Division

constructive algorithms, dfs and similar, graphs, greedy

Palindromic Problem

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

Two Colors

*special problem

Pumping Lemma

hashing, strings

Contingency Plan 2

graph matchings

Grid Game 2

games, number theory

Spaceship Exploration

binary search, geometry

Cursed Game

interactive

Beautiful Tree

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

Landscaping

binary search, geometry, two pointers

Local Deletions

binary search, data structures, implementation

Game of Stacks

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

Hard Design

greedy, implementation, math

Last Man Standing

brute force, data structures, number theory

Jellyfish and Hack

dp, math

Jellyfish and Miku

divide and conquer, dp, math, probabilities

Lazy Numbers

binary search, math

Flower-like Pseudotree

constructive algorithms, graphs, greedy, implementation, trees

Jackets and Packets

dp

Swaps

combinatorics, dp, graphs, math

Evaluate RBS

data structures, geometry, implementation, math, sortings

Game Bundles

brute force, constructive algorithms, dp, greedy, math

Michael and Hotel

binary search, interactive, trees

Miriany and Matchstick

constructive algorithms, dp, greedy

Triangle Platinum?

brute force, combinatorics, implementation, interactive, math, probabilities

Swimmers in the Pool

dp, fft, math, number theory

Tree Weights

bitmasks, constructive algorithms, data structures, dfs and similar, implementation, math, matrices, number theory, trees

Min Cost Permutation (Hard Version)

binary search, constructive algorithms, data structures, greedy, math, sortings

Tenzing and Random Real Numbers

bitmasks, dp, graphs, math, probabilities

Tenzing and Random Operations

combinatorics, dp, math, probabilities

Stuck Conveyor

binary search, constructive algorithms, interactive

Doctor's Brown Hypothesis

dfs and similar, graphs, math, number theory

Mex Tree

brute force, dp, trees

Two Centroids

data structures, dfs and similar, greedy, trees

Fading into Fog

geometry, interactive, math, probabilities

LuoTianyi and the Function

data structures

Misha and Apples

brute force, data structures, dp, two pointers

Last Number

combinatorics, math

M-tree

data structures, math, sortings, trees

Prediction

combinatorics, dp, math

Minibuses on Venus (hard version)

brute force, combinatorics, dp, math

GCD Master (hard version)

greedy, math, sortings

GCD Master (easy version)

greedy, math, number theory, sortings

Gasoline prices

data structures, divide and conquer, dsu, hashing, trees

Li Hua and Path

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

Strange Triples

brute force, math, number theory

Graph Coloring (hard version)

brute force, combinatorics, divide and conquer, dp, fft, graphs

Colorful Tree Again

brute force, data structures, trees

Weighed Tree Radius

data structures, divide and conquer, implementation, trees

The Game of the Century

constructive algorithms, graphs, shortest paths

Parmigiana With Seafood

binary search, dp, greedy, trees

Teamwork

constructive algorithms, greedy, math

Jumbled Trees

constructive algorithms, math

Game of Questions

bitmasks, combinatorics, dp, fft, math, probabilities

Wonderful Jump

dp, greedy

MCF

flows

Hero to Zero

graph matchings, math

Infinite Chess

implementation, shortest paths

Doremy's Perfect DS Class (Medium Version)

binary search, interactive

Doremy's Perfect DS Class (Easy Version)

binary search, interactive

Edge Queries

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

Decent Division

constructive algorithms, data structures

Distance to the Path

data structures, dfs and similar, trees

Circular Xor Reversal

bitmasks, constructive algorithms

List Generation

combinatorics, dp, math

Kazaee

data structures, hashing, probabilities

Antifibonacci Cut

bitmasks, combinatorics, constructive algorithms, data structures, dp, hashing, math

Anti-Increasing Addicts

constructive algorithms, dp, greedy, math

Pebbles and Beads

data structures, geometry

Location

data structures, dp, math, number theory

Late For Work (submissions are not allowed)

data structures, greedy, schedules, shortest paths

Imitating the Key Tree

combinatorics, dsu, trees

Deducing Sortability

binary search, bitmasks, math

Matching Reduction

brute force, constructive algorithms, dfs and similar, flows, graph matchings, graphs, interactive

Lost Array

bitmasks, combinatorics, constructive algorithms, dp, math

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

Mark and the Online Exam

bitmasks, constructive algorithms, interactive, probabilities