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

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

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

Tree Queries

dfs and similar, graphs, trees

String Compression

dp, hashing, string suffix structures, strings

Madness

constructive algorithms, dfs and similar, trees

Liar

binary search, dp, hashing, string suffix structures

Mister B and Flight to the Moon

constructive algorithms, graphs

Mister B and Astronomers

number theory

Mister B and Beacons on Field

number theory

Four Melodies

flows, graphs

Karen and Neighborhood

binary search, constructive algorithms, implementation

Karen and Cards

binary search, combinatorics, data structures, geometry

Karen and Supermarket

brute force, dp, trees

An unavoidable detour for home

combinatorics, dp, graphs, shortest paths

Bipartite Checking

data structures, dsu, graphs

Two Melodies

dp, flows

Sagheer and Kindergarten

dfs and similar, graphs, implementation, trees

Vladik and Entertaining Flags

data structures, dsu, graphs

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

Card Game

binary search, flows, graphs

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

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

Marmots (hard)

math, probabilities

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

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

Sequence Recovery

bitmasks, data structures, greedy

Exam Cheating

binary search, dp

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

Mages and Monsters

data structures, geometry

Colored Balls

greedy, math, number theory

New task

data structures

Finding lines

constructive algorithms, divide and conquer, interactive

ALT

data structures, flows, graphs, trees

Rap God

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

Till I Collapse

data structures, divide and conquer

Intranet of Buses

binary search, geometry, implementation, two pointers

Andryusha and Nervous Barriers

data structures, dp

Axel and Marston in Bitland

bitmasks, dp, graphs, matrices

Selling Numbers

dp, sortings

Parquet Re-laying

constructive algorithms

Peterson Polyglot

brute force, dfs and similar, dsu, hashing, strings, trees

Sherlock and the Encrypted Data

bitmasks, combinatorics, dp

Sherlock's bet to Moriarty

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

University Schedule

*special problem

Perfectionist Arkadiy

*special problem, number theory

Pens And Days Of Week

*special problem, binary search, number theory

Test Data Generation

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

Blog Post Rating

data structures, sortings

Perishable Roads

dp, graphs, shortest paths

Verifying Kingdom

binary search, divide and conquer, interactive, trees

Varying Kibibits

bitmasks, dp

Bear and Isomorphic Points

geometry, two pointers

Bear and Rectangle Strips

dp, greedy

Bear and Company

dp

The Winds of Winter

binary search, data structures

Change-free

greedy

Math, math everywhere

brute force, dp, math, meet-in-the-middle, number theory

Souvenirs

data structures

Timofey and our friends animals

data structures, divide and conquer, dsu

Timofey and a flat tree

data structures, graphs, hashing, shortest paths, trees

Timofey and remoduling

brute force, implementation, math, number theory

Tree nesting

combinatorics, graphs, trees

Dasha and Photos

brute force, data structures, dp, implementation

Geometrical Progression

brute force, math, number theory

Broken Tree

dfs and similar, dp, graphs, greedy, trees

Can Bash Save the Day?

data structures, divide and conquer, graphs, trees

Team Rocket Rises Again

data structures, graphs, shortest paths

Bash Plays with Functions

brute force, combinatorics, dp, number theory

Long number

expression parsing, math, number theory

Byteland coins

combinatorics, dp, math

Bacterial Melee

brute force, combinatorics, dp, string suffix structures

PolandBall and Many Other Balls

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

PolandBall and Gifts

bitmasks, dp, greedy

PolandBall and White-Red graph

constructive algorithms, graphs, shortest paths