Distance to Different

combinatorics, dp, math

Permutation Problem (Simple Version)

binary search, brute force, combinatorics, data structures, math, number theory

Maximize the Largest Component (Hard Version)

data structures, dfs and similar, dp, dsu, implementation

I Love Balls

combinatorics, math, probabilities

Number of k-good subarrays

bitmasks, brute force, combinatorics, divide and conquer, dp, math, meet-in-the-middle

Yasya and the Mysterious Tree

bitmasks, data structures, dfs and similar, graphs, greedy, strings, trees

XORificator

bitmasks, brute force, greedy, hashing

Chain Queries

binary search, data structures, dfs and similar, implementation, trees

±1

2-sat, dfs and similar, graphs

Min-Fund Prison (Medium)

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

Playing Quidditch (Hard)

implementation

Playing Quidditch (Medium)

implementation

Playing Quidditch (Easy)

implementation

Trails (Hard)

dp, matrices

Arithmancy (Easy)

brute force, constructive algorithms, interactive, strings

Exact Neighbours (Hard)

constructive algorithms

Exact Neighbours (Medium)

constructive algorithms

Division + LCP (hard version)

binary search, brute force, data structures, dp, hashing, math, string suffix structures, strings

Fenwick Tree

bitmasks, brute force, combinatorics, data structures, dp, math, trees

Reverse Card (Hard Version)

brute force, math, number theory

Folding Strip

constructive algorithms, greedy, strings

The Most Reckless Defense

bitmasks, brute force, constructive algorithms, dp, flows, graph matchings, shortest paths

Chain Reaction

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

Scooter

graphs, greedy

Dating

greedy, sortings, trees

Clique Partition

brute force, constructive algorithms, graphs, greedy, implementation

Girl Permutation

combinatorics, dp, math, number theory

Tree Compass

constructive algorithms, dfs and similar, greedy, trees

Farm Game

combinatorics, games

Learning to Paint

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

There and Back Again

Personality Test

Duplicates

XOR Break --- Solo Version

bitmasks, constructive algorithms, greedy

Turtle Magic: Royal Turtle Shell Pattern

bitmasks, brute force, combinatorics, constructive algorithms, dfs and similar, math

Turtle Mission: Robot and the Earthquake

dfs and similar, dp, graphs, shortest paths

Moving Platforms

graphs, math, number theory, shortest paths

Sum over all Substrings (Hard Version)

bitmasks, divide and conquer, dp, dsu, greedy, implementation, strings

Sasha and the Wedding Binary Search Tree

brute force, combinatorics, data structures, dfs and similar, math, trees

Sasha and the Happy Tree Cutting

bitmasks, brute force, dfs and similar, dp, graphs, greedy, math, trees

Modular Sequence

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

Paint Charges

data structures, dp, greedy, math

Vlad and Avoiding X

bitmasks, brute force, dfs and similar, dp, implementation

Space Harbour

data structures, implementation, math, sortings

Mischievous Shooter

brute force, data structures, divide and conquer, dp, implementation

Counting Binary Strings

combinatorics, dp, math

Wine Factory (Easy Version)

data structures, greedy

01 Tree

constructive algorithms, data structures, dsu, greedy, sortings, trees

ace5 and Task Order

constructive algorithms, divide and conquer, implementation, interactive, probabilities, sortings

Yet Another Inversions Problem

combinatorics, data structures, dp, implementation, math, number theory

Happy Life in University

data structures, dfs and similar, greedy, trees

Light Bulbs (Hard Version)

combinatorics, data structures, dfs and similar, dp, graphs, hashing

Light Bulbs (Easy Version)

brute force, combinatorics, dfs and similar, dp, dsu, graphs, math, trees

Array Collapse

data structures, divide and conquer, dp, trees

Joy of Pokémon Observation

Evaluate It and Back Again

constructive algorithms, implementation, math

Blueprint for Seating

combinatorics, divide and conquer, math

Maximum Sum Subarrays

*special problem, dp

Small Permutation Problem (Easy Version)

brute force, combinatorics, dp, math

Lights

brute force, constructive algorithms, dfs and similar, graphs, greedy, implementation

Count BFS Graph

combinatorics, dp

Twin Friends

combinatorics, dp

Maximize The Value

data structures, sortings

Compressed Tree

dfs and similar, dp, graphs, greedy, sortings, trees

Transitive Graph

dfs and similar, dp, dsu, graphs, implementation

Sofia and Strings

data structures, greedy, sortings, strings, two pointers

Permutation Sorting

data structures, sortings

Infinite Card Game

binary search, brute force, data structures, dfs and similar, dp, dsu, games, graphs, greedy, sortings, two pointers

Monocarp and the Set

combinatorics, data structures, math

Counting Rhyme

dp, math, number theory

wxhtzdy ORO Tree

binary search, bitmasks, brute force, data structures, dfs and similar, implementation, trees

Autosynthesis

constructive algorithms, dfs and similar, graphs, greedy, sortings

Jellyfish and EVA

dp, graphs, greedy, math, probabilities

Another MEX Problem

bitmasks, brute force, dp, shortest paths

Candy Party (Hard Version)

bitmasks, constructive algorithms, dp, greedy, implementation, math

Salyg1n and Array (hard version)

constructive algorithms, interactive

Imagination Castle

dp, games, two pointers

Happy Sets

combinatorics

Grouped Carriages

binary search, data structures, dp, flows, greedy

Digital Wallet

dp, greedy

Exotic Queries

data structures, implementation, sortings

Guess Game

bitmasks, data structures, games, math, probabilities, sortings, strings, trees

Speedrun

brute force, dfs and similar, dp, graphs, greedy, math, sortings, two pointers

Non-Intersecting Subpermutations

combinatorics, dp, implementation, math

Balanced String

dp

Trees and Segments

brute force, data structures, dp, greedy, two pointers

More Wrong

divide and conquer, interactive

Earn or Unlock

bitmasks, brute force, dp

Max to the Right of Min

binary search, data structures, divide and conquer, dp, dsu, two pointers

Vika and Bonuses

binary search, brute force, math, ternary search

Omsk Metro (hard version)

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

Tenzing and Triangle

data structures, dp, geometry, greedy, math

Fill the Matrix

data structures, greedy, math

In Search of Truth (Easy Version)

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

Railguns

brute force, dfs and similar, dp, graphs

Ball Sorting

data structures, dp, sortings

Bracket Walk

data structures, greedy, strings

Playoff Fixing

combinatorics, trees

MEX of LCM

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

Combinatorics Problem

brute force, combinatorics, dp