Swaps

combinatorics, dp, graphs, math

Ice Cream Balls

binary search, combinatorics, constructive algorithms, math

Non-Intersecting Subpermutations

combinatorics, dp, implementation, math

Counting Graphs

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

Longest Divisors Interval

brute force, combinatorics, greedy, math, number theory

Expected Destruction

combinatorics, dp, math, probabilities

The Morning Star

combinatorics, data structures, geometry, implementation, math, sortings

Vika and Wiki

binary search, bitmasks, combinatorics, divide and conquer, dp, math

Triangle Platinum?

brute force, combinatorics, implementation, interactive, math, probabilities

Multiple of Three Cycles

combinatorics, data structures, dp, dsu, math

Apple Tree

combinatorics, dfs and similar, dp, math, trees

Sum in Binary Tree

bitmasks, combinatorics, math, trees

Tenzing and Random Operations

combinatorics, dp, math, probabilities

Ski Resort

combinatorics, math, two pointers

Binary Cafe

bitmasks, combinatorics, math

Count Supersequences

combinatorics, dp, math

Playoff Fixing

combinatorics, trees

Old Mobile

combinatorics, dp, probabilities

Ira and Flamenco

combinatorics, constructive algorithms, data structures, implementation, math, sortings, two pointers

Combinatorics Problem

brute force, combinatorics, dp

Hyperregular Bracket Strings

combinatorics, greedy, hashing, math, number theory, sortings

Don't Blame Me

bitmasks, combinatorics, dp, math

Counting Orders

combinatorics, math, sortings, two pointers

LuoTianyi and the Floating Islands (Hard Version)

combinatorics, dfs and similar, math, probabilities, trees

LuoTianyi and the Floating Islands (Easy Version)

combinatorics, math, probabilities, trees

A-characteristic

combinatorics, constructive algorithms, math

Timber

combinatorics, dp, fft, math

Matching

combinatorics, math

Similar Polynomials

combinatorics, math

XOR Counting

bitmasks, combinatorics, dp, math

Vlad and the Nice Paths (hard version)

binary search, combinatorics, data structures, dp, math, two pointers

Vlad and the Nice Paths (easy version)

combinatorics, dp, math

Last Number

combinatorics, math

Prediction

combinatorics, dp, math

Minibuses on Venus (hard version)

brute force, combinatorics, dp, math

Minibuses on Venus (medium version)

combinatorics, divide and conquer, dp, matrices

Minibuses on Venus (easy version)

combinatorics, divide and conquer, dp

DSU Master

combinatorics, dp, dsu, math

Count Voting

combinatorics, dp, math

Triangle Coloring

combinatorics, math

Counting Factorizations

combinatorics, divide and conquer, dp, math, number theory

Graph Coloring (hard version)

brute force, combinatorics, divide and conquer, dp, fft, graphs

Graph Coloring (easy version)

combinatorics, dp, graphs

Serval and Toxel's Arrays

combinatorics, dp, implementation, math

Moving Dots

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

Game on Axis

combinatorics, dfs and similar, dsu, graphs, implementation

Infinite Game

brute force, combinatorics, dp, games, probabilities

Wooden Spoon

combinatorics, dp

Bracket Insertion

combinatorics, dp, math, trees

Three Chairs

bitmasks, brute force, combinatorics, data structures, dp, number theory, sortings

Flexible String Revisit

combinatorics, dp, math, probabilities

Score of a Tree

bitmasks, combinatorics, dfs and similar, dp, math, probabilities, trees

Emordnilap

combinatorics, greedy, math

Another Wine Tasting Event

combinatorics, constructive algorithms, math, strings

Segment Covering

brute force, combinatorics, constructive algorithms, data structures, dp, trees

Game of Questions

bitmasks, combinatorics, dp, fft, math, probabilities

Dominoes

combinatorics, flows, graph matchings, greedy

Hossam and Combinatorics

combinatorics, math, sortings

Koxia and Sequence

bitmasks, combinatorics, dp, math, number theory

Koxia and Tree

combinatorics, dfs and similar, dp, dsu, math, probabilities, trees

Partial Sorting

combinatorics, math, number theory

Playoff

combinatorics, constructive algorithms, dp, greedy, math

Card Guessing

combinatorics, dp, probabilities

Doremy's Pegging Game

combinatorics, dp, math

Valid Bitonic Permutations

combinatorics, dp, implementation, math, number theory

Tree Sum

combinatorics, math, trees

Binary Strings are Fun

combinatorics, math

Anti-median (Hard Version)

combinatorics, dp, math

Carry Bit

combinatorics, math

Tick, Tock

combinatorics, dfs and similar, dsu, graphs

Doping

combinatorics, dp, math

Majority

combinatorics, dp, math, strings

Count GCD

combinatorics, math, number theory

Counting Arrays

combinatorics, dp, math, number theory

ConstructOR

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

List Generation

combinatorics, dp, math

Antifibonacci Cut

bitmasks, combinatorics, constructive algorithms, data structures, dp, hashing, math

Password

brute force, combinatorics, implementation, math

Conditional Mix

combinatorics, dp, math

Card Game

combinatorics, constructive algorithms, dp, games

Balance Addicts

combinatorics, dp, math, two pointers

Ela Goes Hiking

combinatorics, dp, math, probabilities

Meta-set

brute force, combinatorics, data structures, hashing, math

Bestie

brute force, combinatorics, constructive algorithms, implementation, math, number theory

Function Sum

brute force, combinatorics, dp, fft, math

Maximums and Minimums

combinatorics, data structures, divide and conquer, number theory

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Illumination

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

A Certain Magical Party

combinatorics, data structures, greedy, sortings

Almost Perfect

combinatorics, fft, math

Imitating the Key Tree

combinatorics, dsu, trees

Electrical Efficiency

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

Circular Mirror

binary search, combinatorics, geometry, math, two pointers

Madoka and The Corruption Scheme

combinatorics, constructive algorithms, greedy, math

Bags with Balls

combinatorics, dp, math, number theory

Monoblock

combinatorics, data structures, implementation, math

Lost Array

bitmasks, combinatorics, constructive algorithms, dp, math

LCM Sum (easy version)

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

Partial Virtual Trees

combinatorics, dfs and similar, dp, math, trees

Mark and Professor Koro

binary search, bitmasks, brute force, combinatorics, data structures, greedy