A Good Problem

bitmasks, constructive algorithms, math

Line Segments

geometry, greedy, math

Add or XOR

bitmasks, greedy, math

Shifts and Swaps

data structures, graphs, hashing, trees

Grid Coloring

constructive algorithms, geometry, greedy, math

Red Light, Green Light (Hard version)

binary search, brute force, data structures, dfs and similar, dp, graphs, implementation, math, number theory

Red Light, Green Light (Easy version)

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

Make It Beautiful

bitmasks, data structures, greedy, math

Make It Permutation

constructive algorithms

Equal Subsequences

constructive algorithms, greedy

Incessant Rain

data structures, divide and conquer, sortings

Omg Graph

brute force, dsu, graphs, greedy, shortest paths, sortings

Wildflower

combinatorics, dfs and similar, trees

Lost Soul

brute force, greedy

Retaliation

binary search, math, number theory

Cool Partition

data structures, greedy

Shrink

constructive algorithms

False Alarm

greedy, implementation

Gellyfish and Baby's Breath

greedy, math, sortings

Gellyfish and Tricolor Pansy

games, greedy

Gellyfish and Lycoris Radiata (Hard Version)

data structures

Gellyfish and Lycoris Radiata (Easy Version)

data structures

Gellyfish and Mayflower

dp, graphs

Gellyfish and Forget-Me-Not

bitmasks, dp, games, greedy, math

Gellyfish and Eternal Violet

combinatorics, dp, greedy, math, probabilities

Gellyfish and Camellia Japonica

brute force, constructive algorithms, dfs and similar, dp, graphs, greedy, trees

Gellyfish and Flaming Peony

constructive algorithms, dp, math, number theory

Build an Array

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

Small Operations

binary search, brute force, dfs and similar, dp, math, number theory, sortings

Kirei Attacks the Estate

dfs and similar, dp, greedy, trees

Come a Little Closer

brute force, greedy, implementation, math

Need More Arrays

dp, greedy

Not Quite a Palindromic String

greedy, math

Square Year

binary search, brute force, math

Two Arrays

constructive algorithms, dfs and similar, graphs, math

From Kazan with Love

dfs and similar, graphs, implementation, trees

Cheater

binary search, constructive algorithms, greedy, implementation

Smilo and Minecraft

brute force, constructive algorithms, greedy

Good Start

constructive algorithms, math

Shashliks

greedy, math

Variables and Operations

graphs, greedy, shortest paths

Tree Colorings

combinatorics, dfs and similar, dp, graphs, math, number theory, trees

Reachability and Tree

constructive algorithms, dfs and similar, graphs, trees

Coloring Game

binary search, brute force, greedy, two pointers

Shrinking Array

brute force, greedy

Race

implementation, math

Divisible Subarrays

binary search, bitmasks, brute force, data structures, interactive

Puzzle

brute force, constructive algorithms, greedy, math

Changing the String

binary search, data structures, greedy, implementation, sortings, strings

Creating a Schedule

constructive algorithms, data structures, greedy, implementation, sortings

Equal Values

brute force, greedy, two pointers

Fibonacci Cubes

brute force, dp, implementation, math

Energy Crystals

greedy, implementation, math

Faculty

brute force, greedy, math, number theory

Melody

dfs and similar, graphs, implementation

Fewer Batteries

binary search, dfs and similar, dp, graphs, greedy, hashing

Racing

constructive algorithms, greedy

Down with Brackets

strings

Fashionable Array

implementation, sortings

Penguin Steps

binary search, dfs and similar, flows, graphs, shortest paths

Binary String Wowee

combinatorics, dp, strings

D/D/D

dfs and similar, graphs, greedy, shortest paths

Hacking Numbers (Hard Version)

constructive algorithms, interactive, math, number theory

Hacking Numbers (Medium Version)

constructive algorithms, interactive, math, number theory

Hacking Numbers (Easy Version)

bitmasks, constructive algorithms, interactive, math, number theory

Slice to Survive

bitmasks, greedy, math

It's Time To Duel

implementation

Fallen Towers

binary search, greedy

Spruce Dispute

constructive algorithms, dfs and similar, graphs, greedy, implementation, shortest paths, trees

Needle in a Numstack

binary search, brute force, implementation, interactive

Neo's Escape

binary search, brute force, data structures, dp, dsu, graphs, greedy, implementation

SUMdamental Decomposition

bitmasks, constructive algorithms, greedy, implementation, math

Permutation Warm-Up

combinatorics, greedy, math

Cycling (Hard Version)

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

Cycling (Easy Version)

binary search, brute force, dp, greedy

Ain and Apple Tree

binary search, constructive algorithms, greedy, math, trees

Apple Tree Traversing

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

Maximum Subarray Sum

binary search, constructive algorithms, dp, implementation, math

Apples in Boxes

games, greedy, math

LRC and VIP

greedy, number theory

Baudelaire (hard version)

binary search, dfs and similar, divide and conquer, implementation, interactive, trees

Baudelaire (easy version)

binary search, constructive algorithms, divide and conquer, greedy, interactive, trees

Goblin

dfs and similar, dp, dsu, greedy, math

Wolf

binary search, greedy, math

Flower Boy

binary search, dp, greedy, two pointers

Cherry Bomb

greedy, math, sortings

St. Chroma

constructive algorithms, greedy, math

Dr. TC

brute force, math

Modulo 3

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

Numbers and Strings

binary search, brute force, dfs and similar, dp, implementation, math

Unpleasant Strings

binary search, dp, greedy, strings

Array and GCD

binary search, greedy, math, number theory

Card Game

brute force, constructive algorithms, games, greedy, math

Move to the End

brute force, data structures, dp, greedy, implementation

Three Decks

math

Maximize Nor

bitmasks, data structures, dp, implementation, sortings

Keep the Sum

constructive algorithms, implementation, two pointers

Local Construction

constructive algorithms, dfs and similar, implementation, two pointers

Median Splits

binary search, greedy, implementation, sortings

Binary Typewriter

greedy, math