Coin Games

games, math

Contest Proposal

brute force, greedy

Card Pairing

dp, greedy

Unique Array

binary search, data structures, divide and conquer, dp, greedy

Shop Game

data structures, greedy, sortings

Minimizing the Sum

dp

Shifts and Sorting

constructive algorithms, greedy

Two Friends

graphs, implementation, math

Next and Prev

brute force, data structures, schedules

Again Counting Arrays (Hard Version)

combinatorics, dp

Again Counting Arrays (Easy Version)

combinatorics, dp, fft, math

Long Way to be Non-decreasing

binary search, dfs and similar, implementation, two pointers

Fenwick Tree

combinatorics, data structures, dp, math, matrices, trees

Reverse Card (Hard Version)

brute force, math, number theory

Reverse Card (Easy Version)

brute force, math, number theory

Permutation Counting

binary search, implementation, math, sortings

Rectangle Filling

constructive algorithms

Card Exchange

chinese remainder theorem, flows, greedy, string suffix structures

Conference

data structures, flows

Connected Cubes

constructive algorithms, games

Missing Subarray Sum

constructive algorithms

Folding Strip

constructive algorithms, greedy, strings

Missing Subsequence Sum

bitmasks, constructive algorithms, greedy, number theory

Everything Nim

games, greedy, math, sortings

Frequency Mismatch (Hard Version)

binary search, data structures, dfs and similar, hashing, probabilities, trees

Frequency Mismatch (Easy Version)

binary search, data structures, divide and conquer, hashing, probabilities, trees

Carousel of Combinations

brute force, combinatorics, dp, math, number theory

A BIT of an Inequality

bitmasks, brute force, dp, math

How Does the Rook Move?

combinatorics, dp, math

A BIT of a Construction

bitmasks, constructive algorithms, greedy, implementation

Stickogon

constructive algorithms, greedy

Nene and the Passing Game

constructive algorithms, data structures, dsu, graphs, sortings

Nene vs. Monsters (Hard Version)

brute force, greedy, implementation, math

Nene vs. Monsters (Easy Version)

brute force, implementation, math

Nene and the Mex Operator

bitmasks, brute force, constructive algorithms, divide and conquer, dp, greedy, implementation, math

Nene's Magical Matrix

constructive algorithms, greedy, math

Nene and the Card Game

games, greedy

Nene's Game

binary search, brute force, data structures, games, greedy

The Most Reckless Defense

bitmasks, brute force, constructive algorithms, dp, flows, graph matchings, shortest paths

GCD on a grid

brute force, dfs and similar, dp, implementation, math, number theory

Unfair Game

dp, games, greedy, math, schedules

Long Inversions

brute force, greedy, implementation, sortings

Inaccurate Subsequence Search

data structures, two pointers

Inhabitant of the Deep Sea

greedy, implementation, math

Progressive Square

constructive algorithms, data structures, implementation, sortings

Yogurt Sale

math

Unique Strings

combinatorics, dp, math

Chain Reaction

binary search, data structures, dsu, greedy, implementation, math, number theory

Colored Balls

combinatorics, dp, math, sortings

Long Multiplication

greedy, math, number theory

Make It Ugly

implementation, math

Painting the Ribbon

constructive algorithms, greedy, math

Help, what does it mean to be "Based"

brute force, constructive algorithms, expression parsing, implementation, sortings

Dark Matter

bitmasks, geometry

Palindrome

implementation, strings

Mathematician Takeover

binary search, dfs and similar, math

Grid

brute force

Sweep Line

combinatorics, games, math

Are You a Procrastinator?

implementation

They Have Fooled

brute force, schedules

Is it stated?

strings

Are You a Robot, Again?

strings

Growing Trees

binary search, constructive algorithms, flows, graphs, greedy

Thanos Snap

binary search, dp, games, greedy, trees

Clacking Balls

combinatorics, math, probabilities

Inversion Composition

constructive algorithms, data structures, greedy

No Palindromes

brute force, constructive algorithms, divide and conquer, greedy, hashing, implementation, math, strings

Buying Jewels

constructive algorithms, greedy, math

Ticket Hoarding

greedy, math, sortings

Battle Cows

binary search, data structures, greedy

Dual Trigger

constructive algorithms, greedy, math

Shuffling Songs

bitmasks, dfs and similar, dp, graphs, hashing, implementation, strings

0, 1, 2, Tree!

bitmasks, brute force, greedy, implementation, trees

Nearly Shortest Repeating Substring

brute force, implementation, number theory, strings

Product of Binary Decimals

brute force, dp, implementation, number theory

Clock Conversion

implementation, math

Upscaling

implementation

Stair, Peak, or Neither?

implementation

Make Triangle

constructive algorithms, math

Amanda the Amoeba

graphs, implementation, trees, two pointers

Disks

dfs and similar, geometry, graph matchings, graphs

Division Avoidance

greedy, math

Scooter

graphs, greedy

Dating

greedy, sortings, trees

Damage per Second

brute force, math

Funny or Scary?

constructive algorithms

Annual Ants' Gathering

dfs and similar, dp, greedy, trees

Charming Meals

binary search, brute force, greedy, sortings

Grove

brute force, dfs and similar, dp, geometry, probabilities

MST with Matching

bitmasks, brute force, dsu, graph matchings, trees

Rare Coins

combinatorics, math, probabilities

Clique Partition

brute force, constructive algorithms, graphs, greedy, implementation

Tandem Repeats?

brute force, strings, two pointers

Arrow Path

brute force, constructive algorithms, dfs and similar, dp, graphs, shortest paths

Array Fix

brute force, dp, greedy, implementation

Special Characters

brute force, constructive algorithms

Nobody is needed

2-sat, data structures, dfs and similar, dp

Girl Permutation

combinatorics, dp, math, number theory

Birthday Gift

bitmasks, brute force, constructive algorithms, greedy, implementation

Tree Cutting

binary search, dp, greedy, implementation, trees