Multithreading (Hard Version)

combinatorics, implementation, math

Seollal

graphs

Conference Problem

dp

Mini Metro

dp

Evil

math

Hellish Constraints

brute force, dp, two pointers

A Convex Game

dsu, games

Distinguish four Pauli gates

TIE fighter

Moonwalk challenge

data structures, strings, trees

The Tournament

Suns and Rays

dfs and similar, implementation

Fibonacci Strings

strings

Array sorting

*special problem, sortings

Build Railway Stations

*special problem, greedy, trees

Suns and Rays

constructive algorithms, dfs and similar, implementation

Trains and Airplanes

dfs and similar, graphs, shortest paths, trees

Little Brother

binary search, geometry, sortings

Stock Trading

dp

Deja Vu

constructive algorithms, graphs, implementation

Cursed Game

interactive

AI Takeover

interactive

Row of Models

greedy, sortings

Ordering T-Shirts

greedy

Messages on a Tree

Mrs. Hudson's Pancakes

brute force, dp

Diamond Theft

data structures, greedy

Cursor Distance

Berland Traffic

math, matrices

Omkar and Mosaic

combinatorics, constructive algorithms, math

Military Trainings

Jellyfish and OEIS

dp

Rivalries

constructive algorithms, data structures, greedy

Minimal Subset Difference

dp

New Year Running

number theory, trees

Decent Division

constructive algorithms, data structures

Cyclic Sum

data structures, fft, number theory

Neural Network Problem

*special problem, binary search, greedy

Mateusz and Escape Room

dp

Cutting the Line

string suffix structures, strings

Projectors

flows, graphs

Maximum Product?

brute force, combinatorics, dp, greedy, implementation, math, two pointers

Koxia and Bracket

divide and conquer, fft, math

Passports

dp, implementation

Byteland coins

combinatorics, dp, math

Princess and Her Shadow

constructive algorithms, shortest paths

Blocks and Sensors

brute force

Binary notation

*special problem

Alphabetic Tree

binary search, data structures, dfs and similar, hashing, string suffix structures, strings, trees

Ali goes shopping

*special problem, brute force, strings

ASCII Automata Art

Пограничные врата

Suns and Rays

Attraction Score

Treasure Hunt

data structures, divide and conquer, two pointers

Framing Pictures

geometry

BubbleSquare Tokens

So Mean

interactive, math

Bob and stages

dp, geometry

Four Suits

binary search, bitmasks, flows, greedy

Maximum Adjacent Pairs

constructive algorithms, graph matchings

Low Budget Inception

brute force, geometry

Strange device

binary search, interactive, math, trees

Restore the Tree

graphs, greedy, trees

Levenshtein distance

*special problem

Caesar Cipher

*special problem

The Beaver's Problem - 3

Narrow Paths

*special problem, combinatorics

Johnny and New Toy

data structures, implementation, math

Detect Robots

data structures, strings

Reformat the String

*special problem

Three Trees

Grid Game 2

games, number theory

Burenka, an Array and Queries

data structures, math, number theory

Milutin's Plums

interactive

Circle of Numbers

math

Sasha Circle

geometry, math

Landscaping

binary search, geometry, two pointers

Good Graph

bitmasks, dfs and similar, graph matchings, graphs, implementation

Bugaboo

bitmasks, constructive algorithms, dp, number theory

Creeper

Array Covering

data structures

On Iteration of One Well-Known Function

math

Lost Nodes

constructive algorithms, dp, graphs, interactive, sortings, trees

DAG

constructive algorithms

The Ultimate LIS Problem

data structures, greedy

Shift It!

constructive algorithms

Red Blue Tree

data structures, implementation, trees

Photographs (II)

Turing's Award

data structures, dp

Knightmare (hard)

graphs, interactive, shortest paths

Number Deletion Game

*special problem, dp, games, greedy

New Year Cactus

dp

The Films

brute force

R3D3’s Summer Adventure

dp, greedy

PermutationForces

data structures, greedy

Moving Walkways

data structures, greedy, math

Heidi Learns Hashing (Hard)

fft, math, number theory

Fake bullions

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

Rap God

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