Triangles

combinatorics, graphs, math

Partial Sums

combinatorics, math, number theory

Permutation Sum

bitmasks, combinatorics, dp, implementation, meet-in-the-middle

Little Elephant and Elections

brute force, combinatorics, dp

Table

bitmasks, combinatorics, dp, math

Lucky Permutation

brute force, combinatorics, number theory

Short Permutation Problem

combinatorics, dp, fft, math

Modular Stability

combinatorics, math, number theory

Number of Simple Paths

combinatorics, dfs and similar, graphs, trees

Square Subsets

bitmasks, combinatorics, dp, math

Number of Subsequences

combinatorics, dp, strings

Counting Graphs

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

Roman and Numbers

bitmasks, brute force, combinatorics, dp, number theory

Shuffle

combinatorics, math, two pointers

Placing Jinas

combinatorics, math

Moving Dots

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

Guess the Permutation

binary search, combinatorics, interactive, math

Counting Arrays

combinatorics, dp, math, number theory

Coprime Subsequences

bitmasks, combinatorics, number theory

Unusual Sequences

bitmasks, combinatorics, dp, math, number theory

Intercity Travelling

combinatorics, math, probabilities

Roman Digits

brute force, combinatorics, dp, greedy, math

Games with Rectangle

combinatorics, dp

Doremy's Pegging Game

combinatorics, dp, math

Not Quite Lee

combinatorics, dp, math, number theory

One-Dimensional Puzzle

combinatorics, math, number theory

Iahub and Permutations

combinatorics, math

Cipher

combinatorics, dp

Vitaly and Cycle

combinatorics, dfs and similar, graphs, math

Yaroslav and Two Strings

combinatorics, dp

PLEASE

combinatorics, dp, implementation, math, matrices

Mike and Geometry Problem

combinatorics, data structures, dp, geometry, implementation

Little Elephant and LCM

binary search, combinatorics, dp, math

Bubble Strike

combinatorics, math, probabilities, ternary search

Circular Mirror

binary search, combinatorics, geometry, math, two pointers

Parquet

combinatorics, constructive algorithms, greedy, implementation

Playing with Superglue

combinatorics, constructive algorithms

Narrow Paths

*special problem, combinatorics

Two Arrays

binary search, brute force, combinatorics, constructive algorithms, dp, two pointers

Height All the Same

combinatorics, constructive algorithms, math, matrices

Arena

combinatorics, dp, math

Monocarp and the Set

combinatorics, data structures, math

Permutation Shift

brute force, combinatorics, constructive algorithms, dfs and similar, dsu, graphs, math

Common Number

binary search, combinatorics, dp, math

Number of Components

combinatorics, data structures, dp, math

Game on Sum (Easy Version)

combinatorics, dp, games, math

Increase Sequence

combinatorics, dp

ConstructOR

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

Preorder

combinatorics, divide and conquer, dp, dsu, hashing, sortings, trees

Playlist for Polycarp (easy version)

bitmasks, combinatorics, dp

Flexible String Revisit

combinatorics, dp, math, probabilities

Range Deleting

binary search, combinatorics, data structures, two pointers

Colorings and Dominoes

combinatorics, dp, greedy, math

Counting Binary Strings

combinatorics, dp, math

Carry Bit

combinatorics, math

Weird journey

combinatorics, constructive algorithms, dfs and similar, dsu, graphs

Staircases

brute force, combinatorics, data structures, dfs and similar, dp, implementation, math

Mashmokh and Reverse Operation

combinatorics, divide and conquer

Random Task

binary search, bitmasks, combinatorics, dp, math

Cut Substrings

combinatorics, dp, hashing, strings, two pointers

Lengthening Sticks

combinatorics, implementation, math

Assimilation IV

combinatorics, dp, math, probabilities, two pointers

Another Wine Tasting Event

combinatorics, constructive algorithms, math, strings

Vlad and the Nice Paths (easy version)

combinatorics, dp, math

Inverse Coloring

combinatorics, dp, math

Lucky Subsequence

combinatorics, dp, math

Key Storage

combinatorics, math

GukiZ and Binary Operations

combinatorics, implementation, math, matrices, number theory

Order book

combinatorics, data structures, greedy

Light Bulbs (Easy Version)

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

Greg and Friends

combinatorics, dp, graphs, shortest paths

Desk Disorder

combinatorics, dfs and similar, dsu, graphs, trees

Special Matrices

combinatorics, dp

Happy Sets

combinatorics

Devu and Birthday Celebration

combinatorics, dp, math

Magic Trick

combinatorics, math, probabilities

Compartments

combinatorics, constructive algorithms, greedy, implementation

String Mark

combinatorics, math, strings

Blueprint for Seating

combinatorics, divide and conquer, math

Vasily the Bear and Beautiful Strings

combinatorics, math, number theory

Count BFS Graph

combinatorics, dp

Periodical Numbers

combinatorics, dp, number theory

White, Black and White Again

combinatorics, number theory

Cowboys

combinatorics, dp, math

Gerald and Giant Chess

combinatorics, dp, math, number theory

Sum of Paths

combinatorics, dp, math

Phoenix and Computers

combinatorics, dp, math

Winter is here

combinatorics, dp, math, number theory

Divisor Paths

combinatorics, graphs, greedy, math, number theory

Priority Queue

combinatorics, dp, implementation, math, ternary search

Mocha and Stars

combinatorics, dp, fft, math, number theory

Girl Permutation

combinatorics, dp, math, number theory

Playoff Fixing

combinatorics, trees

Combinatorics Problem

brute force, combinatorics, dp

Short Colorful Strip

combinatorics, dfs and similar, dp

Star MST

combinatorics, dp, graph matchings, math

High Cry

binary search, bitmasks, combinatorics, data structures, divide and conquer

Valid Bitonic Permutations

combinatorics, dp, implementation, math, number theory

Palindrome-less Arrays

combinatorics, divide and conquer, dp

Pluses everywhere

combinatorics, dp, math, number theory