Construct Matrix

constructive algorithms, math

Yet Another Inversions Problem

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

Watering an Array

brute force, greedy, implementation, math

Matrix Rank (Hard Version)

combinatorics, dp, math, matrices, string suffix structures

Matrix Rank (Easy Version)

brute force, combinatorics, dp, math, matrices

Optimizations From Chelsu

divide and conquer, dp, number theory, trees

Group Division

constructive algorithms, dfs and similar, graphs, greedy

Happy Life in University

data structures, dfs and similar, greedy, trees

Mathematical Problem

brute force, constructive algorithms, geometry, math

Bicycles

graphs, greedy, implementation, shortest paths, sortings

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

Programming Competition

dfs and similar, dp, graph matchings, greedy, trees

Palindromic Problem

binary search, data structures, hashing, string suffix structures, strings

Matrix Problem

flows, graphs

Array Collapse

data structures, divide and conquer, dp, trees

Kim's Quest

bitmasks, combinatorics, dp

Joy of Pokémon Observation

Innovative Washing Machine

geometry, math, two pointers

Hypercatapult Commute

graphs

Great City Saint Petersburg

data structures

Fugitive Frenzy

math, probabilities

Evaluate It and Back Again

constructive algorithms, implementation, math

Divisibility Test

math

Cactus Transformation

constructive algorithms

Blueprint for Seating

combinatorics, divide and conquer, math

Accumulator Apex

data structures, implementation, sortings

Two Colors

*special problem

Inverse Problem

*special problem, combinatorics, dp

Sum of Digits of Sums

*special problem, binary search, data structures

Pool Records

*special problem, greedy

Build Railway Stations

*special problem, greedy, trees

Maximum Sum Subarrays

*special problem, dp

Remove and Add

*special problem, greedy

Poisonous Swamp

*special problem, *special problem, implementation, implementation

Security Guard

*special problem, greedy

Short Permutation Problem

combinatorics, dp, fft, math

Parallel Swaps Sort

constructive algorithms, data structures

Pumping Lemma

hashing, strings

Small Permutation Problem (Hard Version)

combinatorics, dp, math

Small Permutation Problem (Easy Version)

brute force, combinatorics, dp, math

Multiple Lamps

bitmasks, brute force, constructive algorithms, math, number theory

Split Plus K

greedy, math, number theory

Lights

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

Shift and Reverse

greedy, sortings

Good Triples

brute force, combinatorics, number theory

Triangle Construction

greedy, math

Palindromic Parentheses

constructive algorithms

Deck-Building Game

divide and conquer, math

Count BFS Graph

combinatorics, dp

Contingency Plan 2

graph matchings

Twin Friends

combinatorics, dp

Grid Game 2

games, number theory

Maximize The Value

data structures, sortings

Merge Not Sort

constructive algorithms, dp

Spaceship Exploration

binary search, geometry

Cursed Game

interactive

Button Pressing

bitmasks, constructive algorithms, hashing

Field Should Not Be Empty

brute force, data structures, divide and conquer

One-X

combinatorics, dfs and similar, dp, math, trees

Cyclic MEX

data structures, implementation, math, two pointers

Beautiful Tree

data structures, dfs and similar, graphs, implementation, trees

Tree Queries

data structures, dfs and similar, graphs, implementation, trees

Set To Max (Hard Version)

constructive algorithms, data structures, divide and conquer, greedy, implementation, sortings

Set To Max (Easy Version)

brute force, constructive algorithms, greedy

Babysitting

2-sat, binary search, data structures, graphs, trees

Geo Game

greedy, interactive, math

Maximum And Queries (hard version)

bitmasks, divide and conquer, dp, greedy

Maximum And Queries (easy version)

binary search, bitmasks, brute force, greedy

Trees and XOR Queries Again

data structures, dfs and similar, divide and conquer, graphs, implementation, math, trees

Collapsing Strings

data structures, strings, trees

Robot Queries

binary search, data structures, dp, implementation

Landscaping

binary search, geometry, two pointers

Compressed Tree

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

Yet Another Monster Fight

binary search, dp, greedy, implementation, math

Local Deletions

binary search, data structures, implementation

Transitive Graph

dfs and similar, dp, dsu, graphs, implementation

Small GCD

bitmasks, brute force, dp, math, number theory

Unusual Entertainment

data structures, dfs and similar, dsu, shortest paths, sortings, trees, two pointers

Alex's whims

constructive algorithms, graphs, greedy, shortest paths, trees

Vova Escapes the Matrix

brute force, dfs and similar, divide and conquer, shortest paths

Sofia and Strings

data structures, greedy, sortings, strings, two pointers

Absolute Beauty

greedy, math

Colorful Grid

constructive algorithms

Cyclic Hamming (Hard Version)

brute force, dp, fft, math, number theory

Cyclic Hamming (Easy Version)

brute force, divide and conquer, dp, fft, math, number theory

Pepe Racing

constructive algorithms, implementation, interactive, sortings

Bracket Xoring

constructive algorithms, greedy, implementation, math

Permutation Sorting

data structures, sortings

Ones and Twos

binary search, data structures, divide and conquer, math, two pointers

Two Characters, Two Colors

binary search, data structures, dp, flows, greedy

Fancy Arrays

combinatorics, dp, math, matrices

Infinite Card Game

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

XOR Construction

bitmasks, constructive algorithms, data structures, math, string suffix structures, trees

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

Colorful Constructive

constructive algorithms, data structures, greedy

Freedom of Choice

brute force, greedy, implementation

Neutral Tonality

constructive algorithms, greedy, sortings, two pointers

A Growing Tree

data structures, dfs and similar, trees

Brukhovich and Exams

brute force, greedy, implementation, math, sortings