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

Progressions Covering

data structures, greedy

Promising String (hard version)

data structures, implementation, math, strings

Reverse Sort Sum

constructive algorithms, data structures, greedy, implementation, math, two pointers

For Gamers. By Gamers.

binary search, brute force, greedy, math, sortings

K-good

constructive algorithms, math, number theory

Potion Brewing Class

dfs and similar, math, number theory, trees

Nearest Excluded Points

binary search, data structures, dfs and similar, graphs, shortest paths

Counting Shortcuts

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

Rescheduling the Exam

binary search, data structures, greedy, implementation, math, sortings

Tyler and Strings

combinatorics, data structures, implementation

Madoka and the Best School in Russia

constructive algorithms, dp, math, number theory

Weight the Tree

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

Expand the Path

brute force, combinatorics, data structures, implementation, math

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

Not Adding

brute force, dp, math, number theory

Martial Arts Tournament

binary search, brute force, greedy, math

MinOr Tree

bitmasks, dfs and similar, dsu, graphs, greedy

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

Replace the Numbers

constructive algorithms, data structures, dsu, implementation

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

MEX Sequences

dp, math

Messages

brute force, dp, greedy, probabilities, sortings

Escape The Maze (hard version)

dfs and similar, dp, greedy, shortest paths, trees

Not Quite Lee

combinatorics, dp, math, number theory

Arena

combinatorics, dp, math

Treelabeling

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

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