Chattering

Familiar Operations

brute force, graphs, math

Linear Congruential Generator

number theory

Make Square

math

Guess the number

dp, interactive

Make Symmetrical

brute force

Sergey's problem

constructive algorithms, graphs

AB-Strings

constructive algorithms, strings

Guess two numbers

binary search, interactive

Good Subsegments

data structures

Cycles in product

combinatorics, divide and conquer, trees

Prince's Problem

brute force, data structures, math, number theory, trees

NN country

binary search, data structures, trees

Cactus to Tree

dp, graphs, trees

Visible Black Areas

data structures, dsu, geometry, trees

Bandit Blues

combinatorics, dp, fft, math

Icicles

Shortest Path Queries

bitmasks, data structures, dsu, graphs

World of Tank

dp, greedy

A Creative Cutout

brute force, combinatorics, math

Palindrome Partition

dp, string suffix structures, strings

Coins Exhibition

data structures, dp, math

BuberPool Taxi Optimization

*special problem, interactive

May Holidays

data structures, trees

Pollywog

combinatorics, dp, matrices

Substrings in a String

bitmasks, brute force, data structures, string suffix structures, strings

Strongly Connected Tournament

dp, graphs, math, probabilities

New Year and Original Order

dp, math

Nephren Runs a Cinema

chinese remainder theorem, combinatorics, math, number theory

Lust

combinatorics, math, matrices

Mod Mod Mod

binary search, dp, math

Little Brother

binary search, geometry, sortings

Symmetric Projections

geometry

Magic Breeding

bitmasks

Restore the Tree

graphs, greedy, trees

The Overdosing Ubiquity

brute force, dfs and similar, graphs

Mahmoud and Ehab and the final stage

data structures, strings

Circle of Numbers

math

Ordering T-Shirts

greedy

To Play or not to Play

greedy

Bob and stages

dp, geometry

Rainbow Balls

math

Random Elections

bitmasks, brute force, divide and conquer, fft, math

Tournament Construction

constructive algorithms, dp, graphs, greedy, math

Shake It!

combinatorics, dp, flows, graphs

Maximum Flow

flows, graphs

Nikita and game

binary search, dfs and similar, divide and conquer, graphs, trees

Expected Earnings

Future Failure

dp, games

Red-Black Cobweb

data structures, divide and conquer, implementation, trees

Singer House

combinatorics, dp, graphs, trees

Mister B and Flight to the Moon

constructive algorithms, graphs

Mister B and Astronomers

number theory

Mister B and Beacons on Field

number theory

Karen and Neighborhood

binary search, constructive algorithms, implementation

Karen and Cards

binary search, combinatorics, data structures, geometry

Hitchhiking in the Baltic States

data structures, dp

April Fools' Problem (hard)

binary search, data structures, flows

Marmots (hard)

math, probabilities

Mike and code of a permutation

constructive algorithms, data structures, graphs, sortings

Sequence Recovery

bitmasks, data structures, greedy

Leha and security system

data structures

Choosing Carrot

games, math

Julia the snail

data structures, divide and conquer, dp

Problem of offices

constructive algorithms, dfs and similar, dp, trees

New task

data structures

Finding lines

constructive algorithms, divide and conquer, interactive

Selling Numbers

dp, sortings

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

Blog Post Rating

data structures, sortings

Bear and Rectangle Strips

dp, greedy

Timofey and our friends animals

data structures, divide and conquer, dsu

Timofey and a flat tree

data structures, graphs, hashing, shortest paths, trees

Tree nesting

combinatorics, graphs, trees

Team Rocket Rises Again

data structures, graphs, shortest paths

New Year and Finding Roots

constructive algorithms, implementation, interactive, trees

Arpa’s letter-marked tree and Mehrdad’s Dokhtar-kosh paths

data structures, dfs and similar, trees

Gosha is hunting

brute force, data structures, dp, flows, math, probabilities, sortings

Chess Championship

constructive algorithms, flows, greedy, math

Permutations

math, matrices

Family Photos

games, greedy

Goods transportation

dp, flows, greedy

Cyclic Cipher

chinese remainder theorem, data structures, implementation, number theory, two pointers

Research Rover

combinatorics, dp

Andrew and Chemistry

dp, hashing, trees

Cowboy Beblop at his computer

geometry

Festival Organization

combinatorics, math, number theory

Incorrect Flow

flows

Black Widow

dp, graphs, implementation, math

T-Shirts

data structures

Coprime Permutation

combinatorics, number theory

Cron

...Wait for it...

data structures, dsu, trees

TOF

dfs and similar, graphs

Travelling Through the Snow Queen's Kingdom

bitmasks, brute force, divide and conquer, graphs

Optimal Point

binary search, math

The Hero with Bombs

*special problem

Bear and Chase

brute force, dfs and similar, graphs, implementation, math, probabilities