Alesya and Discrete Math

divide and conquer, interactive

Fedor Runs for President

data structures, dp, trees

Serge and Dining Room

binary search, data structures, graph matchings, greedy, implementation, math, trees

Tolik and His Uncle

constructive algorithms

Valeriy and Deque

data structures, implementation

Stock Exchange

binary search, flows, graphs

The Awesomest Vertex

data structures, dfs and similar

Long Colorful Strip

dp

Short Colorful Strip

combinatorics, dfs and similar, dp

Archaeology

brute force, constructive algorithms, greedy, strings

Prime Graph

constructive algorithms, greedy, math, number theory

Tiles

combinatorics, greedy, math

WOW Factor

dp, strings

Prime Minister

greedy

Digits Sequence (Hard Edition)

binary search, divide and conquer, implementation

Digits Sequence (Easy Edition)

implementation

Destroy it!

dp, implementation, sortings

Cover it!

dfs and similar, dsu, graphs, shortest paths, trees

Recover it!

dfs and similar, graphs, greedy, number theory, sortings

Lose it!

dp, greedy, implementation

Merge it!

math

Divide it!

brute force, greedy, implementation

Yet Another Partiton Problem

data structures, divide and conquer, dp, geometry, two pointers

The Number of Subpermutations

brute force, data structures, divide and conquer, hashing, math

Minimal Segment Cover

data structures, dfs and similar, divide and conquer, dp, greedy, implementation, trees

Array Splitting

greedy, sortings

Electrification

binary search, brute force, greedy

Catch Overflow!

data structures, expression parsing, implementation

From Hero to Zero

implementation, math

Ehab and the Big Finale

constructive algorithms, divide and conquer, graphs, implementation, interactive, trees

Ehab and the Expected GCD Problem

combinatorics, dp, math, number theory

Ehab and the Expected XOR Problem

bitmasks, constructive algorithms

Ehab and a Special Coloring Problem

constructive algorithms, number theory

Ehab Is an Odd Person

sortings

Ehab Fails to Be Thanos

constructive algorithms, greedy, sortings

Nauuo and Chess

constructive algorithms, greedy

Nauuo and Votes

greedy

Nauuo and Bug

data structures

Nauuo and ODT

data structures

Nauuo and Portals

constructive algorithms

Nauuo and Pictures (hard version)

dp, probabilities

Nauuo and Pictures (easy version)

dp, probabilities

Nauuo and Circle

combinatorics, dfs and similar, dp, trees

Nauuo and Cards

greedy, implementation

Good Subsets

*special problem, dp

Longest Saw

*special problem, constructive algorithms

Graph Decomposition

*special problem, graphs

Wheels

*special problem, binary search, greedy

Sliding Doors

*special problem, binary search

Decoding of Integer Sequences

*special problem, data structures, implementation

Minus and Minus Give Plus

*special problem, implementation, strings

Bad Days

*special problem, implementation

Three Integers Again

*special problem, math

Pairs

graphs, implementation

Circle Metro

implementation, math

Xor Permutations

constructive algorithms, math

Anagram Paths

dp, implementation, trees

And Reachability

bitmasks, dp

Good Triple

brute force, two pointers

Increasing by Modulo

binary search, greedy

Low Budget Inception

brute force, geometry

Scalar Queries

combinatorics, data structures, math, sortings

Range Deleting

binary search, combinatorics, data structures, two pointers

Bicolored RBS

constructive algorithms, greedy

News Distribution

dfs and similar, dsu, graphs

Lost Numbers

brute force, divide and conquer, interactive, math

Telephone Number

brute force, greedy, strings

Vicky's Delivery Service

data structures, dsu, graphs, hashing

The LCMs Must be Large

bitmasks, brute force, constructive algorithms, math, number theory

Cute Sequences

binary search, brute force, greedy, math

A Tale of Two Lands

binary search, sortings, two pointers

All the Vowels Please

constructive algorithms, math, number theory

Silent Classroom

combinatorics, greedy

Microtransactions (hard version)

binary search, greedy, implementation

Microtransactions (easy version)

binary search, greedy

Two Arrays and Sum of Functions

greedy, math, sortings

Almost All Divisors

math, number theory

Good String

greedy

Polycarp Training

data structures, greedy, sortings

Remainder

implementation, math

Indecisive Taxi Fee

data structures, graphs, shortest paths

Magical Permutation

bitmasks, brute force, constructive algorithms, data structures, graphs, math

Mysterious Code

dp, strings

Power Transmission (Hard Edition)

data structures, geometry, implementation, math

Power Transmission (Easy Edition)

brute force, geometry

Cat Party (Hard Edition)

data structures, implementation

Cat Party (Easy Edition)

data structures, implementation

Eating Soup

greedy, math

Double Matrix

brute force, greedy

Zoning Restrictions Again

implementation

Collaboration

*special problem

Expansion coefficient of the array

implementation, math

A pile of stones

implementation, math

Density of subarrays

dp, math

Strange device

binary search, interactive, math, trees

Winding polygonal line

constructive algorithms, geometry, greedy, math

Permutation recovery

constructive algorithms, data structures, dfs and similar, graphs, greedy, math, sortings

The minimal unique substring

constructive algorithms, math, strings

The Party and Sweets

binary search, constructive algorithms, greedy, implementation, math, sortings, two pointers

Inverse of Rows and Columns

brute force, constructive algorithms