Again Counting Arrays (Hard Version)

combinatorics, dp, math

Again Counting Arrays (Easy Version)

combinatorics, dp, fft, math

Fenwick Tree

bitmasks, brute force, combinatorics, data structures, dp, math, trees

Narrow Paths

*special problem, combinatorics

Carousel of Combinations

brute force, combinatorics, dp, math, number theory

How Does the Rook Move?

combinatorics, dp, math

Unique Strings

combinatorics, dp, math

Colored Balls

combinatorics, dp, math, sortings

Sweep Line

combinatorics, games, math

Clacking Balls

combinatorics, math, probabilities

Rare Coins

combinatorics, math, probabilities

Girl Permutation

combinatorics, dp, math, number theory

Counting Is Fun (Hard Version)

combinatorics, dp

Counting Is Fun (Easy Version)

brute force, combinatorics, dp, math

Bessie and Cards

combinatorics, dp, math

Farm Game

combinatorics, games

Exam in MAC

binary search, combinatorics, implementation, math

Turtle Magic: Royal Turtle Shell Pattern

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

One-Dimensional Puzzle

combinatorics, math, number theory

Chat Screenshots

combinatorics, dfs and similar, graphs

Divisible Pairs

combinatorics, math, number theory

Counting Is Fun

combinatorics

2..3...4.... Wonderful! Wonderful!

combinatorics, dp, math

Sasha and the Wedding Binary Search Tree

brute force, combinatorics, data structures, dfs and similar, math, trees

Sasha and a Walk in the City

combinatorics, dp, math, trees

Digital Patterns

combinatorics, data structures, implementation, math

Good Trip

combinatorics, dp, math, probabilities

Paper Cutting Again

combinatorics, probabilities

Balanced Subsequences

combinatorics, dp, math

Forming Triangles

combinatorics, constructive algorithms, math, sortings

Counting Binary Strings

combinatorics, dp, math

Counting Prefixes

combinatorics, constructive algorithms, dp, implementation, math

Yet Another Inversions Problem

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

Erase First or Second Letter

brute force, combinatorics, data structures, dp, strings

Matrix Rank (Hard Version)

combinatorics, dp, math, matrices, string suffix structures

Matrix Rank (Easy Version)

brute force, combinatorics, dp, math, matrices

Light Bulbs (Hard Version)

combinatorics, data structures, dfs and similar, dp, graphs, hashing

Light Bulbs (Easy Version)

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

Kim's Quest

bitmasks, combinatorics, dp

Blueprint for Seating

combinatorics, divide and conquer, math

Inverse Problem

*special problem, combinatorics, dp

Short Permutation Problem

combinatorics, dp, fft, math

Small Permutation Problem (Hard Version)

combinatorics, dp, math

Small Permutation Problem (Easy Version)

brute force, combinatorics, dp, math

Good Triples

brute force, combinatorics, number theory

Count BFS Graph

combinatorics, dp

Twin Friends

combinatorics, dp

One-X

combinatorics, dfs and similar, dp, math, trees

Fancy Arrays

combinatorics, dp, math, matrices

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

Monocarp and the Set

combinatorics, data structures, math

Sum of XOR Functions

bitmasks, combinatorics, divide and conquer, dp, math

Make it Alternating

combinatorics, dp, greedy

Lexichromatography

combinatorics, dfs and similar, dsu, graphs, two pointers

Effects of Anti Pimples

combinatorics, number theory, sortings

Travel Plan

combinatorics, dp, implementation, math, trees

Mighty Rock Tower

brute force, combinatorics, dp, math, probabilities

Happy Sets

combinatorics

Battling with Numbers

combinatorics, math, number theory

Magic Square

combinatorics, constructive algorithms, implementation

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