Daleks' Invasion (easy)

graphs, trees

Parallel Universes (Hard)

math, matrices

Parallel Universes (Easy)

implementation

Heidi and the Turing Test (Hard)

Heidi and the Turing Test (Medium)

data structures

Heidi and the Turing Test (Easy)

implementation

The Doctor Meets Vader (Hard)

flows, shortest paths

The Doctor Meets Vader (Medium)

flows, graph matchings, graphs, shortest paths, sortings

The Doctor Meets Vader (Easy)

binary search, sortings

Heidi Learns Hashing (Hard)

fft, math, number theory

Heidi Learns Hashing (Medium)

brute force, number theory

Subsequences (hard version)

dp, strings

Candy Box (hard version)

greedy, implementation, sortings

Topforces Strikes Back

brute force, math, sortings

Subsequences (easy version)

dp, graphs, implementation, shortest paths

Candy Box (easy version)

greedy, sortings

Computer Game

binary search, math

Maximum Sine

binary search, data structures, number theory

Product Oriented Recurrence

dp, math, matrices, number theory

Complete Mirror

constructive algorithms, dfs and similar, dp, hashing, implementation, trees

Beautiful Lyrics

data structures, greedy, strings

A Story of One Country (Hard)

brute force, greedy, sortings

A Story of One Country (Easy)

brute force, divide and conquer, sortings

Irrigation

binary search, data structures, implementation, sortings, trees, two pointers

Flag

brute force, combinatorics, dp, implementation

Split a Number

greedy, implementation, strings

Nick and Array

greedy, implementation

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

Digits Sequence (Hard Edition)

binary search, divide and conquer, 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

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

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

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

Pairs

graphs, implementation

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

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

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

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

Double Matrix

brute force, greedy

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

Maximum Balanced Circle

constructive algorithms, dp, greedy, two pointers

Minimum Array

binary search, data structures, greedy

N Problems During K Days

constructive algorithms, greedy, math

Increasing Subsequence (hard version)

greedy

Optimizer

graphs, greedy, hashing, implementation

Card Bag

dp, math, probabilities

Special Segments of Permutation

data structures, divide and conquer, dsu, two pointers