Chain Queries

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

Money Buys Less Happiness Now

data structures, greedy, sortings

±1

2-sat, dfs and similar, graphs

Trails (Medium)

dp, matrices

Arithmancy (Easy)

brute force, constructive algorithms, interactive, strings

Exact Neighbours (Medium)

constructive algorithms

Narrow Paths

*special problem, combinatorics

Nene and the Mex Operator

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

No Palindromes

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

Buying Jewels

constructive algorithms, greedy, math

Clique Partition

brute force, constructive algorithms, graphs, greedy, implementation

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

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

One-Dimensional Puzzle

combinatorics, math, number theory

Sum over all Substrings (Hard Version)

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

Space Harbour

data structures, implementation, math, sortings

Count Paths

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

Counting Binary Strings

combinatorics, dp, math

Tree Diameter

interactive, trees

01 Tree

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

Light Bulbs (Easy Version)

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

Array Collapse

data structures, divide and conquer, dp, trees

Blueprint for Seating

combinatorics, divide and conquer, math

Build Railway Stations

*special problem, greedy, trees

Maximum Sum Subarrays

*special problem, dp

Count BFS Graph

combinatorics, dp

Maximize The Value

data structures, sortings

Cyclic MEX

data structures, implementation, math, two pointers

Geo Game

greedy, interactive, math

Transitive Graph

dfs and similar, dp, dsu, graphs, implementation

Small GCD

bitmasks, brute force, dp, math, number theory

Permutation Sorting

data structures, sortings

Freedom of Choice

brute force, greedy, implementation

A Growing Tree

data structures, dfs and similar, trees

Doremy's Drying Plan (Easy Version)

brute force, data structures, dp, greedy, sortings

Monocarp and the Set

combinatorics, data structures, math

Counting Rhyme

dp, math, number theory

Anya and the Mysterious String

binary search, data structures

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

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

Vlad and the Mountains

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

Pairs of Segments

data structures, greedy, sortings, two pointers

Ball Sorting

data structures, dp, sortings

Bracket Walk

data structures, greedy, strings

Red-Blue Operations (Easy Version)

binary search, greedy, implementation, math

The BOSS Can Count Pairs

brute force, math

Range Sorting (Easy Version)

binary search, dp, dsu, greedy, trees, two pointers

Rearrange Brackets

brute force, dp, greedy, sortings, strings

Sum Graph

brute force, constructive algorithms, graphs, implementation, interactive, shortest paths, trees

Vlad and the Nice Paths (easy version)

combinatorics, dp, math

Is It Flower?

dfs and similar, graphs, implementation

Monsters

brute force, data structures, dfs and similar, dsu, graphs, greedy

Petya, Petya, Petr, and Palindromes

binary search, brute force, data structures, two pointers

Accommodation

brute force, dp, greedy, implementation

The way home

binary search, data structures, dp, graphs, greedy, shortest paths, sortings

Hot Start Up (hard version)

data structures, dp

Maximum Subarray

data structures, dp, greedy, two pointers

Timofey and Black-White Tree

brute force, dfs and similar, divide and conquer, graphs, greedy, math, shortest paths, trees

Moving Dots

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

The Harmonization of XOR

bitmasks, constructive algorithms, greedy, math

Different Arrays

brute force, dp, implementation

Flexible String Revisit

combinatorics, dp, math, probabilities

Another Wine Tasting Event

combinatorics, constructive algorithms, math, strings

The Human Equation

greedy, implementation

Copy of a Copy of a Copy

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

Hossam and (sub-)palindromic tree

brute force, data structures, dfs and similar, dp, strings, trees

Koxia and Game

constructive algorithms, data structures, dfs and similar, dsu, flows, games, graph matchings, graphs, implementation

Count Binary Strings

data structures, dp

Doremy's Pegging Game

combinatorics, dp, math

Another Array Problem

brute force, constructive algorithms, greedy

GCD Queries

constructive algorithms, interactive, number theory

Carry Bit

combinatorics, math

Wish I Knew How to Sort

dp, math, probabilities

ConstructOR

bitmasks, chinese remainder theorem, combinatorics, constructive algorithms, math, number theory

MEX vs MED

math, two pointers

Multi-Colored Segments

binary search, data structures, math, sortings

Rectangular Congruence

constructive algorithms, number theory

Zero-One (Hard Version)

dp, greedy

Sheikh (Hard Version)

binary search, bitmasks, brute force, greedy, implementation, two pointers

Graph Cost

dp, greedy, math, number theory

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Edge Split

brute force, constructive algorithms, dfs and similar, dsu, graphs, probabilities, trees

Field Photography

bitmasks, data structures, sortings

Circular Mirror

binary search, combinatorics, geometry, math, two pointers

Fibonacci Strings

greedy, implementation, math, number theory

Chip Move

brute force, dp, math