Median Queries

constructive algorithms, interactive, probabilities

Oolimry and Suffix Array

combinatorics, constructive algorithms, math

Kill Anton

brute force, constructive algorithms, data structures, math, strings

Goblins And Gnomes

brute force, dp, flows, graph matchings

Assimilation IV

combinatorics, dp, math, probabilities, two pointers

Robot Collisions

data structures, greedy, implementation, sortings

Hopping Around the Array

data structures, dp

Try Booking

data structures, divide and conquer

Favorite Game

bitmasks, dp

Crypto Lights

combinatorics, dp, math, probabilities

Love-Hate

bitmasks, brute force, dp, probabilities

Nastia and a Beautiful Matrix

binary search, constructive algorithms, dp, greedy

Nastia Plays with a Tree

constructive algorithms, data structures, dfs and similar, dp, dsu, greedy, implementation, trees

Nastia and a Hidden Permutation

constructive algorithms, interactive

To Go Or Not To Go?

brute force, dfs and similar, graphs, greedy, implementation, shortest paths

Guess the K-th Zero (Hard version)

binary search, constructive algorithms, data structures, interactive

Chests and Keys

bitmasks, brute force, dfs and similar, dp, flows

Off by One

constructive algorithms, dfs and similar, geometry, graphs, sortings, trees

Fly Around the World

dp, geometry

Starry Night Camping

constructive algorithms, flows, graphs

Reunion

combinatorics, dp, trees

Group Photo

binary search, data structures, implementation, two pointers

Baby Ehab Plays with Permutations

combinatorics, dp, math

Cut

binary search, data structures, dp, graphs, number theory, two pointers

Phoenix and Diamonds

binary search, data structures, sortings

Phoenix and Bits

bitmasks, brute force, data structures, sortings

Phoenix and Odometers

dfs and similar, graphs, math, number theory

Phoenix and Earthquake

constructive algorithms, dfs and similar, dsu, graphs, greedy, trees

Phoenix and Computers

combinatorics, dp, math

Baby Ehab's Hyper Apartment

binary search, graphs, interactive, sortings, two pointers

Cut and Stick

binary search, data structures, greedy, implementation, sortings

Swapping Problem

brute force, constructive algorithms, data structures, sortings

Cost Equilibrium

combinatorics, constructive algorithms, math, sortings

GCD and MST

constructive algorithms, dsu, graphs, greedy, number theory, sortings

Chips on a Board

bitmasks, brute force, data structures, dp, games, two pointers

Chainword

brute force, data structures, dp, matrices, string suffix structures, strings

Colorings and Dominoes

combinatorics, dp, greedy, math

Japanese Game

constructive algorithms, math

Is It Rated?

greedy, interactive, math, probabilities

Hard Optimization

dp

Guide

Fiber Shape

Equilibrium Point /\textbackslash/\textbackslash

Digits

dp, math, number theory

Cactus Not Enough

dfs and similar, graph matchings, graphs

Button Lock

flows, graph matchings, graphs

ASCII Automata Art

Optimal Encoding

brute force, data structures

Tree Calendar

brute force, constructive algorithms, data structures, dfs and similar, sortings, trees

Swap Pass

constructive algorithms, geometry, sortings

Complete the MST

bitmasks, brute force, data structures, dfs and similar, dsu, graphs, greedy, trees

Maximize the Remaining String

brute force, data structures, dp, greedy, strings

Triangular Paths

constructive algorithms, graphs, math, shortest paths, sortings

Mysterious language again, seriously?

*special problem

L BREAK into program

*special problem

Encoded message

*special problem, implementation

Math

*special problem, math

Balance the Cards

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

2-Coloring

combinatorics, dp, math

Flip the Cards

2-sat, constructive algorithms, data structures, greedy, sortings, two pointers

Travelling Salesman Problem

binary search, data structures, dp, greedy, shortest paths, sortings, two pointers

Cupboards Jumps

dp

Subset Trick

binary search, data structures

Tiles for Bathroom

data structures, sortings, two pointers

Matrix Sorting

bitmasks, brute force, constructive algorithms, greedy, two pointers

Two chandeliers

binary search, brute force, chinese remainder theorem, math, number theory

Graph Coloring

data structures, graphs, interactive

Diameter Cuts

combinatorics, dfs and similar, dp, trees

Chaotic Merge

combinatorics, dp, math, strings

The Number of Pairs

dp, math, number theory

Christmas Game

bitmasks, data structures, dfs and similar, dp, games, math, trees

Two Houses

brute force, graphs, greedy, interactive, sortings

Bananas in a Microwave

dfs and similar, dp, graphs, implementation

Square-Free Division (hard version)

data structures, dp, greedy, math, number theory, two pointers

Genius

bitmasks, dp, graphs, number theory

Squares

constructive algorithms, data structures, dp, graphs, trees

Qingshan and Daniel

brute force, data structures, greedy, implementation

BFS Trees

combinatorics, dfs and similar, graphs, math, shortest paths, trees

Garden of the Sun

constructive algorithms, graphs

Delete The Edges

brute force, constructive algorithms, dfs and similar, graphs, implementation

A-Z Graph

constructive algorithms, data structures, graphs, hashing

Dogeforces

constructive algorithms, data structures, dfs and similar, divide and conquer, dsu, greedy, sortings, trees

Enchanted Matrix

bitmasks, interactive, number theory

Enormous XOR

bitmasks, constructive algorithms, greedy, math, strings, two pointers

GCD of an Array

brute force, data structures, hashing, implementation, math, number theory, sortings, two pointers

K-beautiful Strings

binary search, brute force, constructive algorithms, greedy, strings

Almost Fault-Tolerant Database

brute force, constructive algorithms, dfs and similar, greedy, implementation

Ruler Of The Zoo

brute force, data structures

Yuezheng Ling and Dynamic Tree

data structures, trees

Switch and Flip

constructive algorithms, graphs, math

Magnets

binary search, constructive algorithms, interactive

Fib-tree

brute force, dfs and similar, divide and conquer, number theory, trees

Flower Shop

*special problem, data structures, fft, math

Demonic Invasion

*special problem, flows

Build From Suffixes

*special problem, combinatorics, data structures

Painting Numbers

*special problem, data structures, greedy, number theory

Dogecoin

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

Palindromic Doubles

*special problem, data structures, dp

String Counting

combinatorics, dp, fft, math

Ones

dp, greedy, shortest paths