Lucky Pair

combinatorics, data structures, implementation

Ember and Storm's Tree Game

combinatorics, dp, games, trees

Doping

combinatorics, dp, math

Problem from Red Panda

combinatorics

Become Big For Me

combinatorics, constructive algorithms, greedy, math, number theory

Digital Patterns

combinatorics, data structures, implementation, math

Unique Strings

combinatorics, dp, math

Sweep Line

combinatorics, games, math

Special Positions

combinatorics, divide and conquer, fft, math

Old Mobile

combinatorics, dp, probabilities

Days of Floral Colours

combinatorics, divide and conquer, dp, fft, math

Star Trek

*special problem, combinatorics, dfs and similar, dp, games, graphs, matrices, trees

Stairs

combinatorics, divide and conquer, dp, fft, math

Imitating the Key Tree

combinatorics, dsu, trees

Test Data Generation

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

Toys

brute force, combinatorics

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

Game of AI (easy version)

combinatorics, constructive algorithms, dp, fft, math

Drawing Circles is Fun

combinatorics, geometry

Multithreading (Hard Version)

combinatorics, implementation, math

Omkar and Mosaic

combinatorics, constructive algorithms, math

Maximum Product?

brute force, combinatorics, dp, greedy, implementation, math, two pointers

Byteland coins

combinatorics, dp, math

Narrow Paths

*special problem, combinatorics

Fake bullions

combinatorics, dfs and similar, dp, graphs, number theory

Flowers and Chocolate

combinatorics, math, matrices

Multiple of Three Cycles

combinatorics, data structures, dp, dsu, math

Last Number

combinatorics, math

Problems for Codeforces

combinatorics, fft, math

Nezzar and Chocolate Bars

combinatorics, fft, math, probabilities

Again Counting Arrays (Easy Version)

combinatorics, dp, fft, math

Sleeping

combinatorics, implementation, math

Vasily the Bear and Painting Square

bitmasks, combinatorics, dp, implementation

Short Permutation Problem

combinatorics, dp, fft, math

Anti-median (Hard Version)

combinatorics, dp, math

Game of AI (hard version)

combinatorics, fft, math

Three Minimums

combinatorics, constructive algorithms, divide and conquer, dp, fft, math

Intergalactic Sliding Puzzle

combinatorics, constructive algorithms, math

Again Counting Arrays (Hard Version)

combinatorics, dp, math

Build From Suffixes

*special problem, combinatorics, data structures

Counting Is Fun

combinatorics

Inverse Problem

*special problem, combinatorics, dp

Chess Rush

*special problem, combinatorics, dp, implementation, math