Factorial zeros

*special problem

Euler tour

constructive algorithms, trees

Power Substring

math, number theory

Flow Control

data structures, dsu, implementation

Cactus to Tree

dp, graphs, trees

Chessboard

*special problem

Two Circles

brute force, data structures, implementation

Script Generation

Mashmokh's Designed Problem

data structures

Power of quantum Fourier transform

Wizards and Roads

data structures, divide and conquer, graph matchings, graphs, greedy

Two Posters

brute force, data structures, greedy, two pointers

Marek and Matching (hard version)

brute force, probabilities

Marek and Matching (easy version)

brute force, probabilities

Planar Graph

flows, geometry, graphs

Baldman and the military

dfs and similar, graphs, trees

School Clubs

dp, fft, math, number theory, probabilities

Divide The Students

brute force

Double Permutation Inc.

*special problem, binary search, greedy

Hero to Zero

graph matchings, math

Imitating the Key Tree

combinatorics, dsu, trees

New Year and Snowy Grid

dfs and similar, dsu, graphs, interactive

Hammer throwing

*special problem

Kojiro and Furrari

dp, greedy

Privatization

flows, graphs

Vacuum Сleaner

geometry

Игра в Девятку II

*special problem, brute force

Graph Coloring

data structures, graphs, interactive

Minecraft Series

brute force, two pointers

Kingdom Partition

flows

The Meeting Place Cannot Be Changed

dfs and similar, graphs

A Preponderant Reunion

constructive algorithms, dp

Weird LCM Operations

brute force, constructive algorithms, number theory

Test Data Generation

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

Little Artem and 2-SAT

Array Sorting

*special problem

Min-Fund Prison (Hard)

bitmasks, dfs and similar, dp, graphs, trees

Toys

brute force, combinatorics

Tree and Permutation Game

dfs and similar, games, graphs, trees

The Riddle of the Sphinx

binary search, data structures, data structures, interactive

Iqea

data structures, dfs and similar, divide and conquer, dsu, shortest paths, trees

Chess Championship

constructive algorithms, flows, greedy, math

The Tournament

brute force

Infinite Chess

implementation, shortest paths

``Is the bit string periodic?'' oracle

Goshtasp, Vishtasp and Eidi

*special problem, greedy, math

Entangled Substrings

string suffix structures, strings

Growing flowers

data structures

Recover a functional graph

graph matchings

Lift and Throw

brute force

Cacti Symphony

combinatorics, dfs and similar, dp, graphs

Dangerous Laser Power

constructive algorithms, dsu, sortings

Distinguish Y, XZ, -Y and -XZ

``Is the number of ones divisible by 3?'' oracle

Help Monks

constructive algorithms

Long sequence

brute force, math, matrices

Guard Duty (hard)

geometry

Inna and Babies

binary search, data structures, dsu, geometry, implementation

Connected Cubes

constructive algorithms, games

Kotlinforces

*special problem, constructive algorithms, dp

Supercollider

data structures

Number Discovery

math

Generate equal superposition of four basis states

Military Trainings

Maximum Sum Subarrays

*special problem, dp

ELCA

data structures, trees

Domain

*special problem, expression parsing

Three Arrays

*special problem, constructive algorithms, implementation, sortings

Epic Convolution

chinese remainder theorem, fft, math, number theory

Arpa’s abnormal DNA and Mehrdad’s deep interest

data structures, string suffix structures

HQ9+

*special problem

Road Problem

graphs

Two Characters, Two Colors

binary search, data structures, dp, flows, greedy

Perfectionist Arkadiy

*special problem, number theory

Deleting Substrings

Dreamoon Loves AA

binary search, greedy

Tennis Rackets

brute force, geometry

Poachers

dp, games, graphs, trees

Jumping Transformers

dp

Matrix

data structures

Fibonacci Strings

matrices, strings

Tree LGM

constructive algorithms, divide and conquer, games, trees

Minimums or Medians

Game of AI (easy version)

combinatorics, constructive algorithms, dp, fft, math

Escaping on Beaveractor

data structures, implementation, trees

Code Lock

bitmasks, dp

Strange Triples

brute force, math, number theory

Alesya and Discrete Math

divide and conquer, interactive

Sloth

dfs and similar, dp, graph matchings, trees

Sequence Recovery

bitmasks, data structures, greedy

Gena and Second Distance

geometry

Drawing Circles is Fun

combinatorics, geometry

Dogecoin

*special problem, *special problem, binary search, data structures

Alice and the Cactus

dfs and similar, graphs, math, probabilities

Tree and Table

dfs and similar, dp, implementation, trees

Two Sorts

binary search, dfs and similar, math, meet-in-the-middle

Olympic Games

math

Doremy's Paint 2

data structures

Bitwise Magic

dp, math

The Doctor Meets Vader (Hard)

flows, shortest paths