±1

2-sat, dfs and similar, graphs

Min-Fund Prison (Easy)

dfs and similar, trees

Trails (Medium)

dp, matrices

Arithmancy (Easy)

brute force, constructive algorithms, interactive, strings

Game on Tree (Hard)

dfs and similar, dp, games, trees

Exact Neighbours (Medium)

constructive algorithms

Exact Neighbours (Easy)

constructive algorithms

Shop Game

data structures, greedy, math, sortings

Division + LCP (easy version)

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

Narrow Paths

*special problem, combinatorics

Yet Another Permutation Constructive

*special problem, constructive algorithms

A BIT of an Inequality

bitmasks, brute force, dp, math

Nene and the Mex Operator

bitmasks, brute force, constructive algorithms, divide and conquer, dp, greedy, implementation, math

GCD on a grid

brute force, dfs and similar, dp, implementation, math, number theory

No Palindromes

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

Buying Jewels

constructive algorithms, greedy, math

Shuffling Songs

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

Annual Ants' Gathering

dfs and similar, dp, greedy, trees

Clique Partition

brute force, constructive algorithms, graphs, greedy, implementation

Birthday Gift

bitmasks, brute force, constructive algorithms, greedy, implementation

Kirill and Mushrooms

data structures, sortings

Non-Palindromic Substring

hashing, implementation, math, strings

Learning to Paint

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

Rudolf and Subway

constructive algorithms, dfs and similar, graphs, shortest paths

There and Back Again

Bit Counting Sequence

Pinball

binary search, data structures, implementation, math, two pointers

XOR Break --- Solo Version

bitmasks, constructive algorithms, greedy

Turtle Mission: Robot and the Earthquake

dfs and similar, dp, graphs, shortest paths

Feed Cats

data structures, dp, sortings

One-Dimensional Puzzle

combinatorics, math, number theory

Sum over all Substrings (Hard Version)

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

Sasha and a Walk in the City

combinatorics, dp, math, trees

Lonely Mountain Dungeons

brute force, data structures, greedy, math, ternary search

Microcycle

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

Vlad and Trouble at MIT

dfs and similar, dp, flows, graphs, greedy, implementation, trees

Good Trip

combinatorics, dp, math, probabilities

Space Harbour

data structures, implementation, math, sortings

Count Paths

data structures, dfs and similar, dp, dsu, graphs, trees

Berserk Monsters

brute force, data structures, dsu, implementation, math

Sum of Progression

brute force, data structures, dp, implementation, math

Counting Binary Strings

combinatorics, dp, math

Array Repetition

binary search, brute force, dsu, implementation, math

Tree Diameter

interactive, trees

01 Tree

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

Blocking Elements

binary search, data structures, dp, implementation, two pointers

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

Array Collapse

data structures, divide and conquer, dp, trees

Divisibility Test

math

Blueprint for Seating

combinatorics, divide and conquer, math

Accumulator Apex

data structures, implementation, sortings

Build Railway Stations

*special problem, greedy, trees

Maximum Sum Subarrays

*special problem, dp

Short Permutation Problem

combinatorics, dp, fft, math

Split Plus K

greedy, math, number theory

Count BFS Graph

combinatorics, dp

Maximize The Value

data structures, sortings

Merge Not Sort

constructive algorithms, dp

Cyclic MEX

data structures, implementation, math, two pointers

Geo Game

greedy, interactive, math

Collapsing Strings

data structures, strings, trees

Robot Queries

binary search, data structures, dp, 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

Absolute Beauty

greedy, math

Permutation Sorting

data structures, sortings

XOR Construction

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

Freedom of Choice

brute force, greedy, implementation

A Growing Tree

data structures, dfs and similar, trees

Suspicious logarithms

binary search, brute force, math

Doremy's Drying Plan (Easy Version)

brute force, data structures, dp, greedy, sortings

Time Travel

binary search, graphs, shortest paths

Monocarp and the Set

combinatorics, data structures, math

Counting Rhyme

dp, math, number theory

Dances (Hard Version)

binary search, greedy, sortings, two pointers

Tree XOR

bitmasks, dfs and similar, dp, greedy, trees

Anya and the Mysterious String

binary search, data structures

Vasilije Loves Number Theory

brute force, math, number theory

Autosynthesis

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

Replace With Product

brute force, greedy, math

Candy Party (Hard Version)

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

Salyg1n and Array (simple version)

constructive algorithms, interactive, math

Happy Sets

combinatorics

Grouped Carriages

binary search, data structures, dp, flows, greedy

Completely Searching for Inversions

dfs and similar, dp, graphs

Guess Game

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

Speedrun

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

The Great Equalizer

binary search, data structures, math, sortings

Counting Graphs

combinatorics, divide and conquer, dsu, graphs, greedy, sortings, trees

More Wrong

divide and conquer, interactive

Dual (Hard Version)

constructive algorithms, math

Vlad and the Mountains

binary search, data structures, dsu, graphs, implementation, sortings, trees, two pointers

Professor Higashikata

data structures, dsu, greedy, implementation, strings

Rudolf and CodeVid-23

bitmasks, dp, graphs, greedy, shortest paths

Tenzing and His Animal Friends

constructive algorithms, graphs, greedy

Pairs of Segments

data structures, greedy, sortings, two pointers

Ball Sorting

data structures, dp, sortings

Bracket Walk

data structures, greedy, strings