Swimmers in the Pool

dp, fft, math, number theory

Boxes and Balls

dp, implementation, math

Rating System

binary search, brute force, data structures, dp, dsu, greedy, math, two pointers

Strong Password

binary search, dp, greedy, strings

Come Together

geometry, implementation, math

Forbidden Integer

constructive algorithms, implementation, math, number theory

Multiple of Three Cycles

combinatorics, data structures, dp, dsu, math

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

Min Cost Permutation (Easy Version)

brute force, constructive algorithms, greedy, math

Great Grids

2-sat, constructive algorithms, dfs and similar, dsu, graphs

Row Major

constructive algorithms, greedy, math, number theory, strings

Particles

dp, greedy, implementation, math

Permutations & Primes

constructive algorithms, math

Subtraction Game

constructive algorithms, games

Omsk Metro (hard version)

data structures, dfs and similar, divide and conquer, dp, math, trees

Omsk Metro (simple version)

data structures, dfs and similar, dp, graphs, greedy, math, trees

Tracking Segments

binary search, brute force, data structures, two pointers

Apple Tree

combinatorics, dfs and similar, dp, math, trees

Sum in Binary Tree

bitmasks, combinatorics, math, trees

Long Long

greedy, math, two pointers

Sasha and Array Coloring

greedy, sortings, two pointers

Tenzing and Necklace

divide and conquer, dp, greedy

Tenzing and Random Real Numbers

bitmasks, dp, graphs, math, probabilities

Tenzing and Random Operations

combinatorics, dp, math, probabilities

Tenzing and Tree

dfs and similar, greedy, shortest paths, sortings, trees

Tenzing and Triangle

data structures, dp, geometry, greedy, math

Tenzing and His Animal Friends

constructive algorithms, graphs, greedy

Tenzing and Balls

dp

Tenzing and Books

bitmasks, greedy, math

Tenzing and Tsondu

games, math

Monocarp and a Strategic Game

geometry, sortings, two pointers

Fill the Matrix

data structures, greedy, math

Pairs of Segments

data structures, greedy, sortings, two pointers

Ranom Numbers

brute force, dp, greedy, math, strings

Keep it Beautiful

implementation

Game with Board

constructive algorithms, games

In Search of Truth (Hard Version)

constructive algorithms, interactive, math, meet-in-the-middle, probabilities

In Search of Truth (Easy Version)

constructive algorithms, interactive, math, meet-in-the-middle, probabilities

Railguns

brute force, dfs and similar, dp, graphs

Character Blocking

data structures, hashing, implementation

Wooden Toy Festival

binary search, greedy, sortings

Ski Resort

combinatorics, math, two pointers

Binary Cafe

bitmasks, combinatorics, math

Cipher Shifer

implementation, strings, two pointers

Decreasing Game

constructive algorithms, dfs and similar, dp, greedy, interactive

Ball Sorting

data structures, dp, sortings

Insert Zero and Invert Prefix

constructive algorithms

Lamps

greedy, sortings

The Good Array

greedy, implementation, math

Stuck Conveyor

binary search, constructive algorithms, interactive

Count Supersequences

combinatorics, dp, math

Bracket Walk

data structures, greedy, strings

No Prime Differences

constructive algorithms, math, number theory

Minimize Permutation Subarrays

constructive algorithms, math

Blackboard List

constructive algorithms, math

Editorial for Two

binary search, data structures, greedy, implementation

Playoff Fixing

combinatorics, trees

Bracket Coloring

constructive algorithms, greedy

Best Binary String

constructive algorithms, greedy

Comparison String

greedy

Grasshopper on a Line

constructive algorithms, math

Astrophysicists

greedy, math

Destroyer

implementation, sortings

Good Graph

bitmasks, dfs and similar, graph matchings, graphs, implementation

Old Mobile

combinatorics, dp, probabilities

Doctor's Brown Hypothesis

dfs and similar, graphs, math, number theory

Twin Clusters

bitmasks, brute force, constructive algorithms, math, probabilities

Lottery

binary search, brute force, greedy, math, two pointers

k-th equality

brute force, implementation, math

Typewriter

brute force, math

MEX of LCM

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

Survey in Class

brute force, data structures, greedy, implementation, sortings

Game with Reversing

games, greedy, math, strings

Maximum Strength

greedy, math

Unit Array

greedy, math

Ksyusha and Chinchilla

constructive algorithms, dfs and similar, dp, dsu, greedy, implementation, trees

Ira and Flamenco

combinatorics, constructive algorithms, data structures, implementation, math, sortings, two pointers

Round Dance

dfs and similar, dsu, graphs, shortest paths

Flipper

brute force, constructive algorithms, greedy

Vlad Building Beautiful Array

greedy, math

Restore the Weather

greedy, sortings

Musical Puzzle

implementation, strings

Zombies

binary search, dp

Combinatorics Problem

brute force, combinatorics, dp

Red-Blue Operations (Hard Version)

binary search, constructive algorithms, greedy, implementation, math

Red-Blue Operations (Easy Version)

binary search, greedy, implementation, math

Contrast Value

greedy, implementation

Maximum Sum

brute force, sortings, two pointers

New Palindrome

strings

Array merging

constructive algorithms, greedy

Twin Permutations

constructive algorithms

The Third Grace

data structures, dp

Bully Sort

data structures, math

Mex Tree

brute force, dp, trees

Hyperregular Bracket Strings

combinatorics, greedy, hashing, math, number theory, sortings

The BOSS Can Count Pairs

brute force, math

Copil Copac Draws Trees

dfs and similar, dp, graphs, trees

Don't Blame Me

bitmasks, combinatorics, dp, math

Hits Different

data structures, dp, implementation, math