Unique Strings

combinatorics, dp, math

Chain Reaction

binary search, data structures, dsu, greedy, implementation, math, number theory

Colored Balls

combinatorics, dp, math, sortings

Long Multiplication

greedy, math, number theory

Make It Ugly

implementation, math

Painting the Ribbon

constructive algorithms, greedy, math

Accuracy-Preserving Summation Algorithm

*special problem

Help, what does it mean to be "Based"

brute force, constructive algorithms, expression parsing, implementation, sortings

Dark Matter

bitmasks, geometry

Palindrome

implementation, strings

Mathematician Takeover

binary search, dfs and similar, math

Grid

brute force

Sweep Line

combinatorics, games, math

Are You a Procrastinator?

implementation

They Have Fooled

brute force, schedules

Is it stated?

strings

Are You a Robot, Again?

strings

Growing Trees

binary search, constructive algorithms, flows, graphs, greedy

Thanos Snap

binary search, dp, games, greedy, trees

Clacking Balls

combinatorics, math, probabilities

Inversion Composition

constructive algorithms, data structures, greedy

No Palindromes

brute force, constructive algorithms, divide and conquer, greedy, hashing, implementation, math, strings

Buying Jewels

constructive algorithms, greedy, math

Ticket Hoarding

greedy, math, sortings

Battle Cows

binary search, data structures, greedy

Dual Trigger

constructive algorithms, greedy, math

Shuffling Songs

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

0, 1, 2, Tree!

bitmasks, brute force, greedy, implementation, trees

Nearly Shortest Repeating Substring

brute force, implementation, number theory, strings

Product of Binary Decimals

brute force, dp, implementation, number theory

Clock Conversion

implementation, math

Upscaling

implementation

Stair, Peak, or Neither?

implementation

Make Triangle

constructive algorithms, math

Amanda the Amoeba

graphs, implementation, trees, two pointers

Disks

dfs and similar, geometry, graph matchings, graphs

Division Avoidance

greedy, math

Scooter

graphs, greedy

Dating

greedy, sortings, trees

Damage per Second

brute force, math

Funny or Scary?

constructive algorithms

Annual Ants' Gathering

dfs and similar, dp, greedy, trees

Charming Meals

binary search, brute force, greedy, sortings

Grove

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

MST with Matching

bitmasks, brute force, dsu, graph matchings, trees

Rare Coins

combinatorics, math, probabilities

Clique Partition

brute force, constructive algorithms, graphs, greedy, implementation

Tandem Repeats?

brute force, strings, two pointers

Arrow Path

brute force, constructive algorithms, dfs and similar, dp, graphs, shortest paths

Array Fix

brute force, dp, greedy, implementation

Special Characters

brute force, constructive algorithms

Nobody is needed

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

Girl Permutation

combinatorics, dp, math, number theory

Birthday Gift

bitmasks, brute force, constructive algorithms, greedy, implementation

Tree Cutting

binary search, dp, greedy, implementation, trees

Maximum Sum

dp, greedy, math

Median of an Array

greedy, implementation, sortings

GCD is Greater

brute force, data structures, math, number theory

Cook and Porridge

binary search, constructive algorithms, data structures, implementation

Kirill and Mushrooms

data structures, sortings

Binary Search

binary search, constructive algorithms, greedy

Seraphim the Owl

dp, greedy

Left and Right Houses

brute force

Fireworks

math, number theory

Setting up Camp

greedy, math

Equal XOR

bitmasks, constructive algorithms

Destroying Bridges

graphs, greedy, math

Minimum Hamming Distance

dp

MEX Game 2 (Hard Version)

binary search, greedy, two pointers

MEX Game 2 (Easy Version)

binary search, brute force, greedy

Counting Is Fun (Hard Version)

combinatorics, dp

Counting Is Fun (Easy Version)

brute force, combinatorics, dp, math

Tree Compass

constructive algorithms, dfs and similar, greedy, trees

Non-Palindromic Substring

hashing, implementation, math, strings

MEX Game 1

games, greedy

Farmer John's Favorite Intern

data structures, dp, flows, trees

Bessie and Cards

combinatorics, dp, math

Farmer John's Favorite Function

brute force, data structures, implementation, math

Farm Game

combinatorics, games

Learning to Paint

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

Bessie's Birthday Cake (Hard Version)

geometry, greedy, math

Bessie's Birthday Cake (Easy Version)

geometry, greedy, math

Bessie and MEX

constructive algorithms, math

Farmer John's Challenge

constructive algorithms, math

Rudolf and Subway

constructive algorithms, dfs and similar, graphs, shortest paths

Rudolf and Imbalance

binary search, greedy, sortings, two pointers

Rudolf and k Bridges

binary search, data structures, dp, two pointers

Rudolf and the Ball Game

dfs and similar, dp, implementation

Rudolf and the Ugly String

dp, greedy, strings

Rudolf and 121

brute force, dp, greedy, math

Rudolf and the Ticket

brute force, math

Almost Certainly

*special problem, constructive algorithms, data structures, sortings

Burenka and Pether

*special problem, data structures, dfs and similar, divide and conquer, dsu, graphs, sortings, trees

Three Arrays

*special problem, constructive algorithms, implementation, sortings

Parallel Universes

*special problem, constructive algorithms, dfs and similar, dsu, graphs

Big Persimmon

*special problem, dp, games

More Gifts

*special problem, dfs and similar, two pointers

Evidence Board

*special problem, constructive algorithms, dfs and similar, graphs, trees

Draw Polygon Lines

*special problem, constructive algorithms, dp, geometry, interactive

Zig-zag