A Battle Against a Dragon

*special problem, data structures, dp

Inconvenient Pairs

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

Non-Decreasing Dilemma

data structures, divide and conquer, math

Four Vertices

constructive algorithms, data structures, graphs, greedy, implementation, shortest paths

Points Movement

data structures, dp, greedy, implementation, sortings

Seating Arrangements (hard version)

data structures, greedy, implementation, sortings, two pointers

Seating Arrangements (easy version)

data structures, greedy, sortings

Two Hundred Twenty One (hard version)

data structures, math

Two Hundred Twenty One (easy version)

data structures, dp, math

Up the Strip (simplified version)

brute force, data structures, dp, math, number theory

Strange Sort

data structures, sortings

Top-Notch Insertions

combinatorics, data structures

Ezzat and Grid

data structures, dp, greedy

Gates to Another World

bitmasks, data structures, dsu, two pointers

Equilibrium

data structures, dp, greedy

Good Graph

data structures, dsu, graphs, trees

Boring Segments

data structures, sortings, trees, two pointers

Pairwise Modulo

data structures, math

Telepanting

binary search, data structures, dp, sortings

Colors and Intervals

constructive algorithms, data structures, greedy, sortings

Wonderful Coloring - 2

binary search, constructive algorithms, data structures, greedy

Jumping Around

binary search, data structures, divide and conquer, dp, dsu, graphs, shortest paths

Gregor and the Two Painters

data structures, divide and conquer, graphs, greedy, math

Integers Have Friends

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

Array Stabilization (GCD version)

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

Air Conditioners

data structures, dp, implementation, shortest paths, sortings, two pointers

AquaMoon and Potatoes

brute force, data structures, dp

AquaMoon and Time Stop (hard version)

data structures, dp

AquaMoon and Time Stop (easy version)

data structures, dp

Inverse Inversions

binary search, brute force, data structures

Strange Array

data structures, greedy, sortings

Game with Cards

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

Funny Substrings

data structures, hashing, implementation, matrices, strings

Number of Pairs

binary search, data structures, math, two pointers

Erase and Extend (Hard Version)

binary search, data structures, greedy, hashing, string suffix structures, strings, two pointers

Omkar and Medians

data structures, greedy, implementation

Diluc and Kaeya

data structures, dp, hashing, number theory

String Distance

binary search, brute force, data structures, hashing, implementation, strings

Gold Transfer

binary search, data structures, dp, greedy, interactive, trees

Playoff Tournament

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

A New Beginning

data structures, dp, geometry, sortings

Submatrices

*special problem, bitmasks, data structures, dp

Chess Team Forming

*special problem, binary search, data structures, greedy

Sweets

*special problem, data structures, implementation

Turing's Award

data structures, dp

Trees of Tranquillity

data structures, dfs and similar, greedy, trees

Partition Game

binary search, data structures, divide and conquer, dp

Kill Anton

brute force, constructive algorithms, data structures, math, strings

Potions (Hard Version)

data structures, greedy

Potions (Easy Version)

brute force, data structures, dp, greedy

Robot Collisions

data structures, greedy, implementation, sortings

Hopping Around the Array

data structures, dp

Try Booking

data structures, divide and conquer

Compression and Expansion

brute force, data structures, greedy, implementation, trees

Nastia Plays with a Tree

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

Guess the K-th Zero (Hard version)

binary search, constructive algorithms, data structures, interactive

Same Differences

data structures, hashing, math

Berland Regional

brute force, data structures, greedy, number theory, sortings

Group Photo

binary search, data structures, implementation, two pointers

Cut

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

Phoenix and Diamonds

binary search, data structures, sortings

Phoenix and Bits

bitmasks, brute force, data structures, sortings

Phoenix and Towers

constructive algorithms, data structures, greedy

Cut and Stick

binary search, data structures, greedy, implementation, sortings

Swapping Problem

brute force, constructive algorithms, data structures, sortings

Corrupted Array

constructive algorithms, data structures, greedy

Chips on a Board

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

Chainword

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

Yet Another Card Deck

brute force, data structures, implementation, trees

Optimal Encoding

brute force, data structures

Tree Calendar

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

Complete the MST

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

Maximize the Remaining String

brute force, data structures, dp, greedy, strings

Epic Transformation

constructive algorithms, data structures, greedy

Balance the Cards

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

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

Subset Trick

binary search, data structures

Tiles for Bathroom

data structures, sortings, two pointers

Graph Coloring

data structures, graphs, interactive

Minimum Grid Path

brute force, data structures, greedy, math

Christmas Game

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

Planar Reflections

brute force, data structures, dp

Box Fitting

binary search, bitmasks, data structures, greedy

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

Meximization

brute force, data structures, greedy, sortings

Squares

constructive algorithms, data structures, dp, graphs, trees

Qingshan and Daniel

brute force, data structures, greedy, implementation

A-Z Graph

constructive algorithms, data structures, graphs, hashing

Dogeforces

constructive algorithms, data structures, dfs and similar, divide and conquer, dsu, greedy, sortings, trees

GCD of an Array

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

Maximum width

binary search, data structures, dp, greedy, two pointers

Card Deck

data structures, greedy, math

Ruler Of The Zoo

brute force, data structures

Yuezheng Ling and Dynamic Tree

data structures, trees

Pekora and Trampoline

brute force, data structures, dp, greedy, implementation

Old Floppy Drive

binary search, data structures, math

Equalize the Array

binary search, data structures, greedy, math, sortings

Accidental Victory

binary search, data structures, greedy