Permutation of Rows and Columns

constructive algorithms, data structures, hashing, math, matrices, sortings

Trails (Hard)

dp, matrices

Trails (Medium)

dp, matrices

Fractal Origami

geometry, math, matrices

Wine Factory (Hard Version)

data structures, dp, flows, greedy, matrices

Matrix Rank (Hard Version)

combinatorics, dp, math, matrices, string suffix structures

Matrix Rank (Easy Version)

brute force, combinatorics, dp, math, matrices

Fancy Arrays

combinatorics, dp, math, matrices

Asterism Stream

dp, math, matrices

Tree Weights

bitmasks, constructive algorithms, data structures, dfs and similar, implementation, math, matrices, number theory, trees

Chain Chips

data structures, dp, matrices

Minibuses on Venus (medium version)

combinatorics, divide and conquer, dp, matrices

Make It Connected

binary search, brute force, constructive algorithms, dsu, graphs, greedy, matrices, trees, two pointers

Intersection and Union

data structures, dp, matrices, probabilities

Cross Swapping

2-sat, data structures, dsu, greedy, matrices

Points

combinatorics, data structures, implementation, math, matrices

Almost Ternary Matrix

bitmasks, constructive algorithms, matrices

Long Binary String

bitmasks, math, matrices, meet-in-the-middle, number theory

Labyrinth Adventures

data structures, dp, matrices, shortest paths

Cross Xor

constructive algorithms, graphs, math, matrices

European Trip

dp, graphs, math, matrices

Weird Sum

combinatorics, data structures, geometry, math, matrices, sortings

Infinite Set

bitmasks, dp, math, matrices, number theory, strings

Tricolor Triangles

brute force, graphs, math, matrices

William The Oblivious

bitmasks, data structures, dp, matrices

Two Arrays

data structures, matrices

Moamen and XOR

bitmasks, combinatorics, dp, math, matrices

Tasty Dishes

math, matrices

Funny Substrings

data structures, hashing, implementation, matrices, strings

Add One

dp, matrices

Chainword

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

1 2 3 4 ...

dp, math, matrices

Latin Square

math, matrices

Xum

bitmasks, constructive algorithms, math, matrices, number theory

No Game No Life

bitmasks, games, math, matrices

Star Trek

*special problem, combinatorics, dfs and similar, dp, games, graphs, matrices, trees

Strange Addition

data structures, dp, matrices

Cubic Lattice

geometry, math, matrices, number theory

Piet's Palette

matrices

Robots on a Grid

data structures, dfs and similar, dsu, graphs, greedy, matrices

Height All the Same

combinatorics, constructive algorithms, math, matrices

LCC

data structures, math, matrices, probabilities

Red-Blue Graph

dp, graphs, math, matrices, meet-in-the-middle

Addition Robot

data structures, math, matrices

Coloring Game

dp, games, matrices

Count Pairs

math, matrices, number theory, two pointers

Parallel Universes (Hard)

math, matrices

Product Oriented Recurrence

dp, math, matrices, number theory

Neko Rules the Catniverse (Large Version)

bitmasks, dp, matrices

Neko Rules the Catniverse (Small Version)

bitmasks, dp, matrices

Sonya and Informatics

combinatorics, dp, matrices, probabilities

Magic Gems

dp, math, matrices

Lunar New Year and a Recursive Sequence

math, matrices, number theory

(Zero XOR Subset)-less

math, matrices

Colored Cubes

constructive algorithms, implementation, matrices

Down or Right

constructive algorithms, interactive, matrices

Chemical table

constructive algorithms, dfs and similar, dsu, graphs, matrices

A Trance of Nightfall

dp, geometry, matrices, probabilities

Mahmoud and Ehab and yet another xor task

bitmasks, dp, math, matrices

Runner's Problem

dp, matrices, sortings

Fibonacci String Subsequences

combinatorics, dp, matrices

Perpetual Subtraction

fft, math, matrices

Stranger Trees

dp, math, matrices, trees

Pollywog

combinatorics, dp, matrices

Lust

combinatorics, math, matrices

Flowers and Chocolate

combinatorics, math, matrices

Neural Network country

dp, matrices

Prefix Sums

binary search, brute force, combinatorics, math, matrices

Vasya and Shifts

matrices

Okabe and El Psy Kongroo

dp, matrices

Axel and Marston in Bitland

bitmasks, dp, graphs, matrices

New Year and Old Subsequence

data structures, divide and conquer, dp, matrices

Permutations

math, matrices

Sasha and Array

data structures, math, matrices

Dexterina’s Lab

games, matrices, probabilities

Legen...

data structures, dp, matrices, strings

PLEASE

combinatorics, dp, implementation, math, matrices

Xor-sequences

matrices

Gambling Nim

bitmasks, math, matrices, probabilities

Magic Matrix

brute force, divide and conquer, graphs, matrices, trees

Wet Shark and Blocks

dp, matrices

Combining Slimes

dp, math, matrices, probabilities

Strange Calculation and Cats

dp, matrices

Once Again...

constructive algorithms, dp, matrices

Mirror Box

matrices, trees

Flights for Regular Customers

dp, matrices

Fibonotci

data structures, math, matrices

GukiZ and Binary Operations

combinatorics, implementation, math, matrices, number theory

Darth Vader and Tree

dp, matrices

Mr. Kitayuta's Gift

combinatorics, dp, matrices, strings

Stairs and Lines

dp, matrices

Subsequences Return

dp, matrices

Factory

implementation, math, matrices

Design Tutorial: Change the Goal

constructive algorithms, math, matrices

Little Pony and Elements of Harmony

dp, matrices

DZY Loves Bridges

math, matrices

DZY Loves Games

math, matrices, probabilities

Yet Another Number Sequence

combinatorics, math, matrices

Bear in the Field

math, matrices

Jeff and Brackets

dp, matrices