Tree and XOR

strings, trees

Segments on the Line

binary search, dp

Refactoring

greedy, implementation, strings

Lucky Days

math, number theory

Alice and Hairdresser

dsu, implementation

Metro

graphs

Epic Convolution

chinese remainder theorem, fft, math, number theory

New Road Network

constructive algorithms, greedy, math

Electric Scheme

flows, graph matchings

Chips Puzzle

constructive algorithms, implementation, math

Changing Array

greedy, implementation

Candies Distribution

constructive algorithms, implementation

Appending Mex

implementation

Elevator or Stairs?

implementation

Euler tour

constructive algorithms, trees

Distinctification

data structures, dsu, greedy

The Shortest Statement

graphs, shortest paths, trees

Vasya and Big Integers

binary search, data structures, dp, hashing, strings

Bicolorings

bitmasks, dp

Vasya and Multisets

brute force, dp, greedy, implementation, math

Relatively Prime Pairs

greedy, math, number theory

Vasya And Password

greedy, implementation, strings

Cover Points

geometry, math

Little C Loves 3 I

math

Say Hello

geometry

Splitting money

implementation

Space Formula

greedy

Moonwalk challenge

data structures, strings, trees

Palindrome Pairs

hashing, strings

Self-exploration

math

AI robots

data structures

Shady Lady

geometry, math

Ancient civilizations

constructive algorithms, geometry

Interstellar battle

math, probabilities, trees

Hyperspace Highways

dfs and similar, graphs, trees

Space Isaac

hashing, number theory

Last chance

data structures, flows, graph matchings, graphs, trees

DFS

data structures

Grid Sort

implementation

Deduction Queries

data structures, dsu

Optimal Polygon Perimeter

dp, geometry

Intersecting Subtrees

dfs and similar, interactive, trees

The Tower is Going Home

binary search, two pointers

Speckled Band

data structures, divide and conquer, hashing, string suffix structures, strings

Make It One

bitmasks, combinatorics, dp, math, number theory, shortest paths

Train Hard, Win Easy

constructive algorithms, greedy, math, sortings

Mysterious Crime

brute force, combinatorics, math, meet-in-the-middle, two pointers

Smallest Word

constructive algorithms, greedy, implementation

Lost Array

implementation

Elections

implementation, math

Leaf Sets

data structures, dfs and similar, dsu, graphs, greedy, sortings, trees

Vasya and Magic Matrix

dp, math, probabilities

Petya and Array

data structures, divide and conquer, two pointers

Array Product

constructive algorithms, greedy, math

Vitamins

bitmasks, brute force, dp, implementation

Benches

binary search, implementation

Ray in the tube

data structures, divide and conquer, dp, math

Tree Reconstruction

constructive algorithms, data structures, graphs, greedy

Glider

binary search, data structures, two pointers

Coffee Break

binary search, data structures, greedy, two pointers

Buying a TV Set

math

Heist

greedy, implementation, sortings

Shashlik Cooking

dp, greedy, math

Palindrome Dance

greedy

Summer Oenothera Exhibition

data structures

You Are Given a Tree

data structures, dp, trees

Network Safety

dfs and similar, dsu, graphs, math, sortings

Subway Pursuit

binary search, interactive, probabilities

Timetable

constructive algorithms, data structures, greedy, math

Wrap Around

dp, strings

Maximum Matching

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

Slime

dp, greedy, implementation

Gambling

greedy, sortings

Non-Coprime Partition

constructive algorithms, math

Equality

implementation, strings

Security

data structures, string suffix structures

A Game on Strings

games

Maximum Reduction

combinatorics, data structures, math

Trips

graphs

Valid BFS?

dfs and similar, graphs, shortest paths, trees

Equalize

dp, greedy, strings

Reach Median

greedy

Packets

constructive algorithms, greedy, math

Sources and Sinks

bitmasks, brute force, dfs and similar

Relatively Prime Powers

combinatorics, math, number theory

Covered Points

fft, geometry, number theory

Vasya and Arrays

greedy, two pointers

Classy Numbers

combinatorics, dp

Diagonal Walking v.2

math

Function Height

math

Little C Loves 3 III

bitmasks, dp, math

Intervals of Intervals

binary search, data structures, two pointers

Region Separation

combinatorics, dp, number theory, trees

Little C Loves 3 II

brute force, constructive algorithms, flows, graph matchings

Enlarge GCD

number theory

Chip Game

games

Boolean Computer

bitmasks, brute force, fft, math

Hidden Bipartite Graph

binary search, constructive algorithms, dfs and similar, graphs, interactive

Divisors

interactive, math, number theory

Permutation Game

brute force, dp, games