Favorite Game

bitmasks, dp

Crypto Lights

combinatorics, dp, math, probabilities

Love-Hate

bitmasks, brute force, dp, probabilities

Nastia and a Beautiful Matrix

binary search, constructive algorithms, dp, greedy

Nastia Plays with a Tree

constructive algorithms, data structures, dfs and similar, dp, dsu, greedy, implementation, trees

Chests and Keys

bitmasks, brute force, dfs and similar, dp, flows

Fly Around the World

dp, geometry

Reunion

combinatorics, dp, trees

Baby Ehab Plays with Permutations

combinatorics, dp, math

Cut

binary search, data structures, dp, graphs, number theory, two pointers

Phoenix and Computers

combinatorics, dp, math

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

Hard Optimization

dp

Digits

dp, math, number theory

Maximize the Remaining String

brute force, data structures, dp, greedy, strings

2-Coloring

combinatorics, dp, math

Travelling Salesman Problem

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

Cupboards Jumps

dp

Diameter Cuts

combinatorics, dfs and similar, dp, trees

Chaotic Merge

combinatorics, dp, math, strings

The Number of Pairs

dp, math, number theory

Christmas Game

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

Bananas in a Microwave

dfs and similar, dp, graphs, implementation

Square-free division (hard version)

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

Genius

bitmasks, dp, graphs, number theory

Squares

constructive algorithms, data structures, dp, graphs, trees

Palindromic Doubles

*special problem, data structures, dp

String Counting

combinatorics, dp, fft, math

Ones

dp, greedy, shortest paths

Pairs of Paths

combinatorics, data structures, dfs and similar, dp, trees

Paired Payment

binary search, brute force, constructive algorithms, dp, flows, graphs, shortest paths

Max Median

binary search, data structures, dp

Copy or Prefix Sum

combinatorics, data structures, dp, sortings

Move and Swap

dfs and similar, dp, greedy, trees

Skyline Photo

data structures, divide and conquer, dp

AB Tree

dp, greedy, trees

Sorting Books

data structures, dp, greedy

School Clubs

dp, fft, math, number theory, probabilities

Painting the Array II

constructive algorithms, data structures, dp, greedy, implementation

Lanterns

binary search, data structures, dp

1 2 3 4 ...

dp, math, matrices

Cleaning

data structures, dp, greedy, math

Tiles

combinatorics, dp, fft, math

Moving to the Capital

dfs and similar, dp, graphs, shortest paths

New Year's Puzzle

brute force, dp, graph matchings, greedy, sortings

Strange Permutation

binary search, combinatorics, data structures, dp, graphs, implementation, two pointers

LaIS

data structures, dp, greedy

Distinctive Roots in a Tree

data structures, dfs and similar, dp, trees

Sum of Paths

combinatorics, dp, math

Finding satisfactory solutions

combinatorics, dp, graphs, greedy, math

Max Correct Set

bitmasks, dp, math

Mathematical Expression

constructive algorithms, dp, greedy

Glass Half Spilled

dp

XOR-ranges

dp, greedy

Forbidden Value

data structures, dp

String and Operations

dp, greedy

Even Harder

dp

Dog Snacks

binary search, dfs and similar, dp, greedy, trees

Two Editorials

brute force, dp, greedy, sortings, two pointers

Communism

bitmasks, dp, trees

Xor Tree

binary search, bitmasks, data structures, divide and conquer, dp, trees

Finding the Vertex

brute force, dfs and similar, dp, interactive, trees

Rectangular Polyline

constructive algorithms, dp, geometry

Black, White and Grey Tree

binary search, constructive algorithms, dfs and similar, dp, greedy, trees

Sum

data structures, divide and conquer, dp, greedy

INOI Final Contests

combinatorics, dp, fft

Emotional Fishermen

combinatorics, dp, math, two pointers

Make It Increasing

binary search, constructive algorithms, data structures, dp, implementation

Zero Remainder Sum

dp

Zero-XOR Array

*special problem, dp

Number Deletion Game

*special problem, dp, games, greedy

Yet Another DAG Problem

bitmasks, dfs and similar, dp, flows, graphs, math

Realistic Gameplay

dp, greedy

Lucky Numbers (Hard Version)

dp, greedy

Lucky Numbers (Easy Version)

dp, greedy

Fruit Sequences

binary search, data structures, divide and conquer, dp, two pointers

The Hard Work of Paparazzi

dp

Number of Subsequences

combinatorics, dp, strings

Danger of Mad Snakes

combinatorics, dp, math

Blue and Red of Our Faculty!

divide and conquer, dp

Bubble Cup hypothesis

bitmasks, constructive algorithms, dp, math

Minlexes

dp, greedy, implementation, strings

Swedish Heroes

brute force, dp, implementation

Battle Lemmings

dp, greedy

Pokémon Army (hard version)

data structures, divide and conquer, dp, greedy, implementation

Split

binary search, data structures, dp, greedy

XOR Inverse

bitmasks, data structures, divide and conquer, dp, greedy, math, sortings, strings, trees

Cakes for Clones

dp

Subsequences of Length Two

dp, strings

Bitwise Magic

dp, math

Clusterization Counting

combinatorics, dp, dsu, fft, graphs, trees

Searchlights

binary search, brute force, data structures, dp, implementation, sortings, two pointers

Egor in the Republic of Dagestan

constructive algorithms, dfs and similar, dp, graphs, greedy, shortest paths

Discrete Centrifugal Jumps

data structures, dp, graphs

Chess Rush

*special problem, combinatorics, dp, implementation, math

Star Trek

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

Mercenaries

bitmasks, brute force, combinatorics, dp, dsu, math, two pointers

x-prime Substrings

brute force, dfs and similar, dp, string suffix structures, strings