Dark Matter

bitmasks, geometry

Substring Search

bitmasks, brute force, fft

Matvey's Birthday

bitmasks, graphs

Sherlock and the Encrypted Data

bitmasks, combinatorics, dp

Fix the String

*special problem, bitmasks, dp, greedy

Circular Xor Reversal

bitmasks, constructive algorithms

Polycarpus is Looking for Good Substrings

bitmasks, hashing, implementation

Game of Questions

bitmasks, combinatorics, dp, fft, math, probabilities

Gates to Another World

bitmasks, data structures, dsu, two pointers

Nora's Toy Boxes

bitmasks, combinatorics, dp

Long Binary String

bitmasks, math, matrices, meet-in-the-middle, number theory

Misha and XOR

bitmasks

X-mouse in the Campus

bitmasks, math, number theory

Chiori and Doll Picking (hard version)

bitmasks, brute force, combinatorics, math

Bob's Beautiful Array

bitmasks, brute force, greedy

Feeling Good

bitmasks, data structures

Tree Cutting

bitmasks, dfs and similar, dp

Mutation

bitmasks, dp, math

Appropriate Team

bitmasks, math, number theory

Antifibonacci Cut

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

Bitonix' Patrol

bitmasks, brute force, combinatorics, dfs and similar, math

Robot in Basement

bitmasks, brute force, implementation

Communism

bitmasks, dp, trees

Phoenix and Bits

bitmasks, brute force, data structures, sortings

Cheat and Win

bitmasks, data structures, games, trees

Party

bitmasks, brute force, graph matchings

Min-Fund Prison (Hard)

bitmasks, dfs and similar, dp, graphs, trees

Code Lock

bitmasks, dp

Sequence Recovery

bitmasks, data structures, greedy

Four Suits

binary search, bitmasks, flows, greedy

Good Graph

bitmasks, dfs and similar, graph matchings, graphs, implementation

Bugaboo

bitmasks, constructive algorithms, dp, number theory

Hex Dyslexia

bitmasks, brute force, dp, graphs

Deducing Sortability

binary search, bitmasks, math

Vasily the Bear and Painting Square

bitmasks, combinatorics, dp, implementation

Lookup Tables

bitmasks

Mateusz and an Infinite Sequence

bitmasks, brute force, dp, strings

Submatrices

*special problem, bitmasks, data structures, dp

Keep talking and nobody explodes -- easy

bitmasks, brute force, expression parsing

Egg Roulette

bitmasks, brute force, divide and conquer, math, meet-in-the-middle