Product 1 Modulo N

greedy, number theory

AND 0, Sum Big

bitmasks, combinatorics, math

Perfectly Imperfect Array

math, number theory

Swapping Problem

brute force, constructive algorithms, data structures, sortings

Cost Equilibrium

combinatorics, constructive algorithms, math, sortings

GCD and MST

constructive algorithms, dsu, graphs, greedy, number theory, sortings

Add One

dp, matrices

AND Sequences

bitmasks, combinatorics, constructive algorithms, math

Array and Peaks

constructive algorithms, implementation

Short Task

brute force, dp, math, number theory

Education

brute force, dp, greedy, implementation

Permutation by Sum

brute force, greedy, math

Corrupted Array

constructive algorithms, data structures, greedy

A-B Palindrome

constructive algorithms, implementation, strings

Almost Rectangle

implementation

Spy Detected!

brute force, implementation

Chips on a Board

bitmasks, brute force, data structures, dp, games, two pointers

Chainword

brute force, data structures, dp, matrices, string suffix structures, strings

Colorings and Dominoes

combinatorics, dp, greedy, math

Min Cost String

brute force, constructive algorithms, graphs, greedy, strings

Yet Another Card Deck

brute force, data structures, implementation, trees

GCD Length

constructive algorithms, math, number theory

Review Site

greedy

King's Task

brute force, graphs, implementation

Japanese Game

constructive algorithms, math

Is It Rated?

greedy, interactive, math, probabilities

Hard Optimization

dp

Guide

Fiber Shape

Equilibrium Point /\textbackslash/\textbackslash

Digits

dp, math, number theory

Cactus Not Enough

dfs and similar, graph matchings, graphs

Button Lock

flows, graph matchings, graphs

ASCII Automata Art

The Sports Festival

dp, greedy

TMT Document

greedy

Average Height

constructive algorithms

Optimal Encoding

brute force, data structures

Tree Calendar

brute force, constructive algorithms, data structures, dfs and similar, sortings, trees

Swap Pass

constructive algorithms, geometry, sortings

Complete the MST

bitmasks, brute force, data structures, dfs and similar, dsu, graphs, greedy, trees

Almost Sorted

binary search, combinatorics, constructive algorithms, implementation

Binary Literature

constructive algorithms, greedy, implementation, strings, two pointers

Maximize the Remaining String

brute force, data structures, dp, greedy, strings

Triangular Paths

constructive algorithms, graphs, math, shortest paths, sortings

Restoring the Permutation

constructive algorithms, implementation

Epic Transformation

constructive algorithms, data structures, greedy

Double-ended Strings

brute force, implementation, strings

Partial Replacement

greedy, implementation

Strange Table

math

Mysterious language again, seriously?

*special problem

L BREAK into program

*special problem

Encoded message

*special problem, implementation

Math

*special problem, math

Cakewalk

*special problem, greedy, implementation, shortest paths

Xenolith? Hippodrome?

*special problem, number theory

Fibonacci Words

*special problem, implementation

DMCA

*special problem, implementation, number theory

Is it rated - 2

*special problem, implementation, interactive

Flip the Bits

constructive algorithms, greedy, implementation, math

Déjà Vu

constructive algorithms, strings

Balance the Cards

constructive algorithms, data structures, divide and conquer, geometry, graphs, implementation

2-Coloring

combinatorics, dp, math

Flip the Cards

2-sat, constructive algorithms, data structures, greedy, sortings, two pointers

Travelling Salesman Problem

binary search, data structures, dp, greedy, shortest paths, sortings, two pointers

3-Coloring

constructive algorithms, games, interactive

Balance the Bits

constructive algorithms, greedy

Napoleon Cake

dp, implementation, sortings

Alexey and Train

implementation

Cupboards Jumps

dp

Subset Trick

binary search, data structures

Tiles for Bathroom

data structures, sortings, two pointers

Matrix Sorting

bitmasks, brute force, constructive algorithms, greedy, two pointers

Two chandeliers

binary search, brute force, chinese remainder theorem, math, number theory

Going Home

brute force, hashing, implementation, math

Graph Coloring

data structures, graphs, interactive

Diameter Cuts

combinatorics, dfs and similar, dp, trees

Chaotic Merge

combinatorics, dp, math, strings

The Number of Pairs

dp, math, number theory

Minimum Grid Path

brute force, data structures, greedy, math

Binary Removals

brute force, dp, greedy, implementation

Domino on Windowsill

combinatorics, constructive algorithms, math

Christmas Game

bitmasks, data structures, dfs and similar, dp, games, math, trees

Two Houses

brute force, graphs, greedy, interactive, sortings

Bananas in a Microwave

dfs and similar, dp, graphs, implementation

Planar Reflections

brute force, data structures, dp

Box Fitting

binary search, bitmasks, data structures, greedy

GCD Sum

brute force, math

Square-free division (hard version)

data structures, dp, greedy, math, number theory, two pointers

Square-Free Division (easy version)

data structures, dp, greedy, math, number theory, two pointers

Genius

bitmasks, dp, graphs, number theory

k-LCM (hard version)

constructive algorithms, math

k-LCM (easy version)

constructive algorithms, math

M-arrays

constructive algorithms, greedy, math

Meximization

brute force, data structures, greedy, sortings

Max and Mex

math

Split it!

brute force, constructive algorithms, greedy, strings

Squares

constructive algorithms, data structures, dp, graphs, trees

Qingshan and Daniel

brute force, data structures, greedy, implementation

BFS Trees

combinatorics, dfs and similar, graphs, math, shortest paths, trees