MEX vs DIFF

binary search, brute force, constructive algorithms, data structures, greedy, two pointers

Circular Spanning Tree

constructive algorithms, implementation, trees

Moving Chips

bitmasks, dp, greedy

Remove Directed Edges

dfs and similar, dp, graphs

Breaking the Wall

binary search, brute force, constructive algorithms, greedy, math

Array Shuffling

constructive algorithms, graphs, greedy

Preorder

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

Optimal Partition

data structures, dp

Job Lookup

constructive algorithms, dp, shortest paths, trees

GCD Guess

bitmasks, chinese remainder theorem, constructive algorithms, games, interactive, math, number theory

Promising String (hard version)

data structures, implementation, math, strings

For Gamers. By Gamers.

binary search, brute force, greedy, math, sortings

Potion Brewing Class

dfs and similar, math, number theory, trees

Counting Shortcuts

data structures, dfs and similar, dp, graphs, shortest paths

Weight the Tree

constructive algorithms, dfs and similar, dp, implementation, trees

Repetitions Decoding

constructive algorithms, implementation, sortings

Big Brush

constructive algorithms, data structures, greedy, implementation

Best Pair

binary search, brute force, implementation

Finding Zero

constructive algorithms, interactive, math

New Year Concert

binary search, data structures, greedy, math, number theory, two pointers

Game on Sum (Easy Version)

combinatorics, dp, games, math

Martial Arts Tournament

binary search, brute force, greedy, math

Interacdive Problem

binary search, constructive algorithms, interactive

Masha-forgetful

brute force, constructive algorithms, dp, hashing, implementation, strings

Shuffle

combinatorics, math, two pointers

The Winter Hike

constructive algorithms, greedy, math

Exact Change

brute force, constructive algorithms, greedy

Unusual Minesweeper

binary search, dfs and similar, dsu, greedy, sortings

Let's Play the Hat?

brute force, constructive algorithms, greedy, math

Reverse

bitmasks, constructive algorithms, dfs and similar, implementation, math, strings

Keep the Average High

dp, greedy, math

Divan and Kostomuksha (easy version)

dp, number theory

Crazy Robot

dfs and similar, graphs

Messages

brute force, dp, greedy, probabilities, sortings

Not Quite Lee

combinatorics, dp, math, number theory

Arena

combinatorics, dp, math

Treelabeling

bitmasks, constructive algorithms, dfs and similar, games, greedy, implementation, trees

Hidden Fortress

interactive, math

Bubble Strike

combinatorics, math, probabilities, ternary search

Staircases

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

Red-Black Number

dfs and similar, dp, implementation, math, meet-in-the-middle

Guess the Permutation

binary search, combinatorics, interactive, math

Pchelyonok and Segments

binary search, data structures, dp, greedy, math

Longest Array Deconstruction

data structures, divide and conquer, dp, sortings

The Strongest Build

binary search, brute force, data structures, dfs and similar, graphs, greedy, hashing, implementation

Kotlinforces

*special problem, constructive algorithms, dp

Expression Evaluation Error

constructive algorithms, greedy, implementation, math

Buds Re-hanging

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

Nearest Beautiful Number (hard version)

bitmasks, brute force, constructive algorithms, dfs and similar, dp, greedy

Bottom-Tier Reversals

constructive algorithms, greedy

Boring Segments

data structures, sortings, trees, two pointers

Permutation Shift

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

Fixed Points

binary search, brute force, dp

Domino (hard version)

constructive algorithms, implementation, math

How Many Paths?

dfs and similar, dp, graphs, trees

Gift Set

binary search, greedy, math, ternary search

Funny Substrings

data structures, hashing, implementation, matrices, strings

Omkar and Medians

data structures, greedy, implementation

Minimax

constructive algorithms, greedy, strings

Assimilation IV

combinatorics, dp, math, probabilities, two pointers

Robot Collisions

data structures, greedy, implementation, sortings

Nastia and a Hidden Permutation

constructive algorithms, interactive

Cut

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

Cut and Stick

binary search, data structures, greedy, implementation, sortings

GCD and MST

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

Colorings and Dominoes

combinatorics, dp, greedy, math

Guide

Digits

dp, math, number theory

Maximize the Remaining String

brute force, data structures, dp, greedy, strings

Triangular Paths

constructive algorithms, graphs, math, shortest paths, sortings

The Number of Pairs

dp, math, number theory

GCD of an Array

brute force, data structures, hashing, implementation, math, number theory, sortings, two pointers

K-beautiful Strings

binary search, brute force, constructive algorithms, greedy, strings

Cheap Dinner

brute force, data structures, graphs, greedy, implementation, sortings, two pointers

Max Median

binary search, data structures, dp

Skyline Photo

data structures, divide and conquer, dp

AB Graph

brute force, constructive algorithms, graphs, greedy, implementation

Painting the Array II

constructive algorithms, data structures, dp, greedy, implementation

Moving to the Capital

dfs and similar, dp, graphs, shortest paths

New Year's Puzzle

brute force, dp, graph matchings, greedy, sortings

Euclid's nightmare

bitmasks, dfs and similar, dsu, graphs, greedy, math, sortings

Glass Half Spilled

dp

Array Partition

binary search, data structures, greedy, two pointers

Number of Simple Paths

combinatorics, dfs and similar, graphs, trees

Bitwise Queries (Easy Version)

bitmasks, constructive algorithms, interactive, math

Errich-Tac-Toe (Easy Version)

constructive algorithms, math

Xor Tree

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

Engineer Artem

2-sat, chinese remainder theorem, constructive algorithms, fft, flows

Reducing Delivery Cost

brute force, graphs, shortest paths

Zero Remainder Sum

dp

Number Deletion Game

*special problem, dp, games, greedy

Neural Network Problem

*special problem, binary search, greedy

Chess Match

*special problem

Unshuffling a Deck

constructive algorithms, implementation

The Hard Work of Paparazzi

dp

Number of Subsequences

combinatorics, dp, strings

Pokémon Army (hard version)

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

Decryption

constructive algorithms, implementation, math, number theory

Trash Problem

data structures, implementation

XOR Inverse

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