Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

A Convex Game

dsu, games

Tree LGM

constructive algorithms, divide and conquer, games, trees

Epic Convolution

chinese remainder theorem, fft, math, number theory

Growing flowers

data structures

Entangled Substrings

string suffix structures, strings

School Clubs

dp, fft, math, number theory, probabilities

Minecraft Series

brute force, two pointers

New Year and Snowy Grid

dfs and similar, dsu, graphs, interactive

Flow Control

data structures, dsu, implementation

Euler tour

constructive algorithms, trees

Journey

data structures, divide and conquer, graphs, trees

Old Mobile

combinatorics, dp, probabilities

Phoenix and Bits

bitmasks, brute force, data structures, sortings

Stock Exchange

binary search, flows, graphs

OH NO1 (-2-3-4)

constructive algorithms, graphs, math

Become Big For Me

combinatorics, constructive algorithms, greedy, math, number theory

Cheat and Win

bitmasks, data structures, games, trees

Ж-function

string suffix structures, strings

Speckled Band

data structures, divide and conquer, hashing, string suffix structures, strings

Breadboard Capacity (hard version)

Forest Fires

math

Bully Sort

data structures, math

The Fair Nut's getting crazy

data structures, implementation

Xor on Figures

constructive algorithms, fft, math

Communism

bitmasks, dp, trees

JYPnation

graphs

Just Add an Edge

dfs and similar, dp, graphs

Hopping Around the Array

data structures, dp

Zigzag Game

games, interactive

Holy Diver

data structures

Range Diameter Sum

data structures, trees

XOR-ranges

dp, greedy

Jumping Through the Array

binary search, data structures, graphs, two pointers

Modest Substrings

dp, strings

My Beautiful Madness

data structures, trees

Chiori and Doll Picking (hard version)

bitmasks, brute force, combinatorics, math

Nora's Toy Boxes

bitmasks, combinatorics, dp

Minimize Inversions Number

data structures, greedy, math, sortings

Cupboards Jumps

dp

Rin and The Unknown Flower

constructive algorithms, greedy, interactive, math

Making Shapes

dp

Chip Game

games

Cactus Revenge

constructive algorithms

Density of subarrays

dp, math

Beautiful fountains rows

data structures

Intervals of Intervals

binary search, data structures, two pointers

Replace

binary search, data structures

Beautiful Fibonacci Problem

constructive algorithms, number theory

Kuroni and Antihype

bitmasks, brute force, dp, dsu, graphs

Zero-XOR Array

*special problem, dp

Geolocation

geometry

Intergalactic Sliding Puzzle

combinatorics, constructive algorithms, math

Railway Construction

brute force, constructive algorithms, data structures, graphs, shortest paths

Lada Malina

data structures, geometry

Bad Cryptography

math, number theory

Cyclic Hamming (Easy Version)

brute force, divide and conquer, dp, fft, math, number theory

Negative Time Summation

constructive algorithms

Tokitsukaze and Powers

number theory, probabilities

Long number

expression parsing, math, number theory

Yet Yet Another Permutation Problem

divide and conquer, fft, math

Mateusz and an Infinite Sequence

bitmasks, brute force, dp, strings

Shady Lady

geometry, math

Red-Blue Graph

dp, graphs, math, matrices, meet-in-the-middle

Harder Satisfiability

2-sat, dfs and similar, graphs

Minimum Segments

constructive algorithms

Pisces

data structures, flows, trees

Upside Down

data structures, string suffix structures, strings, trees

Organizing a Music Festival

dfs and similar, math

Beauty of a Permutation

constructive algorithms, math

Don't Exceed

math, probabilities

Multiple of Three Cycles

combinatorics, data structures, dp, dsu, math

Differentiating Games

games, interactive

Balls and Pockets

data structures

Rap God

data structures, dfs and similar, hashing, strings, trees

Fake bullions

combinatorics, dfs and similar, dp, graphs, number theory

Turing's Award

data structures, dp

Treasure Hunt

data structures, divide and conquer, two pointers

Koxia and Bracket

divide and conquer, fft, math

Strange device

binary search, interactive, math, trees

So Mean

interactive, math

Passports

dp, implementation

Rivalries

constructive algorithms, data structures, greedy

Mini Metro

dp

Doremy's Paint 2

data structures

Two Sorts

binary search, dfs and similar, math, meet-in-the-middle

Minimums or Medians

Arpa’s abnormal DNA and Mehrdad’s deep interest

data structures, string suffix structures

Number Discovery

math

Recover a functional graph

graph matchings

The Riddle of the Sphinx

binary search, data structures, data structures, interactive

Iqea

data structures, dfs and similar, divide and conquer, dsu, shortest paths, trees

Test Data Generation

combinatorics, divide and conquer, dp, fft, math, number theory

Stairs

combinatorics, divide and conquer, dp, fft, math

Days of Floral Colours

combinatorics, divide and conquer, dp, fft, math

Tree

fft, graphs, trees

Fedya the Potter

binary search, implementation, math, number theory

Caramel Clouds

data structures, dp, sortings

Radix sum

fft, math, number theory