Frog Traveler

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

Array Game

games, greedy, two pointers

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

Half of Same

brute force, math, number theory

Yet Another Sorting Problem

data structures, math

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

Inconvenient Pairs

binary search, data structures, implementation, sortings, two pointers

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

Nearest Beautiful Number (easy version)

binary search, bitmasks, brute force, constructive algorithms, dfs and similar, greedy

Bottom-Tier Reversals

constructive algorithms, greedy

Up the Strip

brute force, dp, math, number theory, two pointers

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

Array Stabilization (GCD version)

binary search, brute force, data structures, divide and conquer, number theory, two pointers

AquaMoon and Chess

combinatorics, math

Need for Pink Slips

bitmasks, brute force, dfs and similar, implementation, math, probabilities

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

Palindrome Game (hard version)

constructive algorithms, games

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

Education

brute force, dp, greedy, implementation

Colorings and Dominoes

combinatorics, dp, greedy, math

Guide

Digits

dp, math, number theory

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

The Number of Pairs

dp, math, number theory

Let's Go Hiking

games, greedy

1D Sokoban

binary search, dp, greedy, implementation, two pointers

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

Genius's Gambit

bitmasks, constructive algorithms, greedy, math

Old Floppy Drive

binary search, data structures, math

Problemsolving Marathon

*special problem, binary search, greedy

Two Policemen

*special problem, binary search, brute force, math

Cheap Dinner

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

Max Median

binary search, data structures, dp

Guessing the Greatest (hard version)

binary search, interactive

Skyline Photo

data structures, divide and conquer, dp

Playlist

data structures, dsu, implementation, shortest paths

AB Graph

brute force, constructive algorithms, graphs, greedy, implementation

Painting the Array II

constructive algorithms, data structures, dp, greedy, implementation

Painting the Array I

constructive algorithms, data structures, dp, greedy, implementation

Nezzar and Binary String

data structures, greedy

Strange Beauty

dp, math, number theory, sortings

Unusual Matrix

2-sat, brute force, constructive algorithms

Moving to the Capital

dfs and similar, dp, graphs, shortest paths

New Year's Puzzle

brute force, dp, graph matchings, greedy, sortings

Strange Definition

bitmasks, graphs, hashing, math, number theory

Three Bags

constructive algorithms, greedy

Euclid's nightmare

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

Pairs

binary search, constructive algorithms, greedy, two pointers

Glass Half Spilled

dp

Array Partition

binary search, data structures, greedy, two pointers

Number of Simple Paths

combinatorics, dfs and similar, graphs, trees

Checkpoints

brute force, constructive algorithms, greedy, math, probabilities

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

Divide and Sum

combinatorics, math, sortings

Binary Table (Hard Version)

constructive algorithms, graphs, greedy, implementation

Engineer Artem

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

Bandit in a City

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

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

String Reversal

data structures, greedy, strings

Bouncing Boomerangs

constructive algorithms, greedy, implementation

Unshuffling a Deck

constructive algorithms, implementation

The Hard Work of Paparazzi

dp

Number of Subsequences

combinatorics, dp, strings

Valuable Paper

binary search, flows, graph matchings, graphs

Hexagons

brute force, constructive algorithms, greedy, implementation, math, shortest paths

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

Make Them Equal

constructive algorithms, greedy, math