Round Subset

dp, math

Roads in the Kingdom

dfs and similar, dp, graphs, trees

The penguin's game

binary search, constructive algorithms, interactive

Caramel Clouds

data structures, dp, sortings

Red-Black Cobweb

data structures, divide and conquer, implementation, trees

Ever-Hungry Krakozyabra

brute force, combinatorics, greedy, math

The Bakery

binary search, data structures, divide and conquer, dp, two pointers

Vasya and Shifts

matrices

Strange Radiation

binary search, implementation, math

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

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

Tree Queries

dfs and similar, graphs, trees

String Compression

dp, hashing, string suffix structures, strings

Minimal Labels

data structures, dfs and similar, graphs, greedy

Madness

constructive algorithms, dfs and similar, trees

Liar

binary search, dp, hashing, string suffix structures

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 Boring Game

games, greedy

Four Melodies

flows, graphs

Level Generation

binary search, math, ternary search

Sofa Thief

brute force, implementation

MEX Queries

binary search, data structures, trees

Choosing The Commander

bitmasks, data structures, trees

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

An unavoidable detour for home

combinatorics, dp, graphs, shortest paths

An overnight dance in discotheque

dfs and similar, dp, geometry, greedy, trees

Bipartite Checking

data structures, dsu, graphs

Army Creation

binary search, data structures

Two Melodies

dp, flows

Sagheer and Apple Tree

games, trees

Sagheer and Kindergarten

dfs and similar, graphs, implementation, trees

Vladik and Entertaining Flags

data structures, dsu, graphs

Vladik and Favorite Game

constructive algorithms, dfs and similar, graphs, interactive

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

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

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

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

Mike and code of a permutation

constructive algorithms, data structures, graphs, sortings

Mike and distribution

constructive algorithms, sortings

Mice and Holes

data structures, dp, greedy, sortings

Array Queries

brute force, data structures, dp

Broken BST

data structures, dfs and similar

Sequence Recovery

bitmasks, data structures, greedy

Exam Cheating

binary search, dp

Police Stations

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

Replace All

combinatorics, dp, math

Leha and security system

data structures

Choosing Carrot

games, math

Labelling Cities

dfs and similar, graphs, hashing

Oleg and chess

data structures, divide and conquer, flows, graph matchings

Julia the snail

data structures, divide and conquer, dp

Problem of offices

constructive algorithms, dfs and similar, dp, trees

Presents in Bankopolis

dp, graphs, shortest paths

Mice problem

geometry, implementation, math, sortings

Mages and Monsters

data structures, geometry

Colored Balls

greedy, math, number theory

Divide by Three

dp, greedy, math, number theory

New task

data structures

Finding lines

constructive algorithms, divide and conquer, interactive

The Great Mixing

dfs and similar, graphs, shortest paths

Weird journey

combinatorics, constructive algorithms, dfs and similar, dsu, graphs

ALT

data structures, flows, graphs, trees

Rap God

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

Till I Collapse

data structures, divide and conquer