Perpetual Motion Machine

constructive algorithms, dp, graphs, implementation, math, trees

Singer House

combinatorics, dp, graphs, trees

Bamboo Partition

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

Cards Sorting

data structures, implementation, sortings

Office Keys

binary search, brute force, dp, greedy, sortings

Dirty Arkady's Kitchen

data structures, dp, graphs, shortest paths

Rusty String

fft, math, strings

Best Edge Weight

data structures, dfs and similar, graphs, trees

DNA Evolution

data structures, strings

High Load

constructive algorithms, greedy, implementation, trees

String Reconstruction

data structures, greedy, sortings, strings

Tree Queries

dfs and similar, graphs, trees

String Compression

dp, hashing, string suffix structures, strings

Minimal Labels

data structures, dfs and similar, graphs, greedy

Multi-judge Solving

greedy, implementation

Five-In-a-Row

brute force, implementation

Madness

constructive algorithms, dfs and similar, trees

Liar

binary search, dp, hashing, string suffix structures

My pretty girl Noora

brute force, dp, greedy, math, number theory

Hacker, pack your bags!

binary search, greedy, implementation, sortings

Okabe and El Psy Kongroo

dp, matrices

Okabe and City

dfs and similar, graphs, shortest paths

Mister B and Flight to the Moon

constructive algorithms, graphs

Mister B and Astronomers

number theory

Mister B and Beacons on Field

number theory

Mister B and PR Shifts

data structures, implementation, math

Mister B and Boring Game

games, greedy

Four Melodies

flows, graphs

Level Generation

binary search, math, ternary search

Card Game Again

binary search, data structures, number theory, two pointers

Multicolored Cars

data structures, implementation

Sofa Thief

brute force, implementation

Permutation Game

implementation

MEX Queries

binary search, data structures, trees

Choosing The Commander

bitmasks, data structures, trees

Imbalanced Array

data structures, divide and conquer, dsu, sortings

Really Big Numbers

binary search, brute force, dp, math

Karen and Neighborhood

binary search, constructive algorithms, implementation

Karen and Cards

binary search, combinatorics, data structures, geometry

Karen and Supermarket

brute force, dp, trees

Karen and Test

brute force, combinatorics, constructive algorithms, math

Karen and Game

brute force, greedy, implementation

An unavoidable detour for home

combinatorics, dp, graphs, shortest paths

An overnight dance in discotheque

dfs and similar, dp, geometry, greedy, trees

An impassioned circulation of affection

brute force, dp, strings, two pointers

Bipartite Checking

data structures, dsu, graphs

Army Creation

binary search, data structures

Two Melodies

dp, flows

The Tag Game

dfs and similar, graphs

The Golden Age

brute force, math

Sagheer and Apple Tree

games, trees

Sagheer and Kindergarten

dfs and similar, graphs, implementation, trees

Sagheer, the Hausmeister

bitmasks, brute force, dp

Vladik and Entertaining Flags

data structures, dsu, graphs

Vladik and Favorite Game

constructive algorithms, dfs and similar, graphs, interactive

Vladik and Memorable Trip

dp, implementation

Surprise me!

divide and conquer, math, number theory, trees

Hitchhiking in the Baltic States

data structures, dp

Find a car

combinatorics, divide and conquer, dp

Glad to see you!

binary search, interactive

Anthem of Berland

dp, strings

Card Game

binary search, flows, graphs

Selling Souvenirs

binary search, dp, greedy, ternary search

Array Division

binary search, data structures, implementation

Fake bullions

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

The same permutation

constructive algorithms

Expected diameter of a tree

binary search, brute force, dfs and similar, dp, sortings, trees

Ice cream coloring

constructive algorithms, dfs and similar, greedy

Periodic RMQ Problem

data structures

Coprime Subsequences

bitmasks, combinatorics, number theory

Roma and Poker

dp, graphs

Magazine Ad

binary search, greedy

Maximal GCD

constructive algorithms, greedy, math

April Fools' Problem (hard)

binary search, data structures, flows

April Fools' Problem (medium)

binary search, flows, graphs

Send the Fool Further! (hard)

dfs and similar, dp, math, trees

Send the Fool Further! (medium)

dp, trees

Fake News (hard)

string suffix structures

Fake News (medium)

constructive algorithms, strings

Marmots (hard)

math, probabilities

Marmots (medium)

math

Marmots (easy)

math

Heidi and Library (hard)

flows

Heidi and Library (medium)

data structures, greedy

Heidi and Library (easy)

greedy

Cut the pie

binary search, data structures, geometry

Beautiful fountains rows

data structures

Aquarium decoration

data structures, greedy, two pointers

Field expansion

brute force, dp, meet-in-the-middle

Fountains

binary search, data structures, implementation

Mike and code of a permutation

constructive algorithms, data structures, graphs, sortings

Mike and distribution

constructive algorithms, sortings

Mike and gcd problem

dp, greedy, number theory

Mice and Holes

data structures, dp, greedy, sortings

Array Queries

brute force, data structures, dp

Broken BST

data structures, dfs and similar

Minimal string

data structures, greedy, strings

Sequence Recovery

bitmasks, data structures, greedy

Exam Cheating

binary search, dp

Police Stations

constructive algorithms, dfs and similar, dp, graphs, shortest paths, trees