Skip to content

Algorithms you can see — 100% free.

0%

0-day streakApprentice

0 XP · 0/638 understood

Daily goal 0/1

Prep plan Browse all

Learn the Basics44

Sorting Techniques11

Arrays & Hashing51

Sliding Window20

Binary Search51

Bit Manipulation24

Heap / Priority Queue21

Binary Search Trees21

Depth-First Search25

Breadth-First Search10

Spiral MatrixFour shrinking boundaries
Rotate Image90° in place · transpose + reverse
Set Matrix ZeroesMarkers in the first row/col

Dynamic Programming65

Green dot = step-by-step walkthrough

← / → to step · space to play

Home/Matrices

Matrices

2-D grids — rotate, spiral, and in-place tricks.

0/ 3 understood · 0%

Walkthroughs: 3
Problems: 3

3 shown

Spiral MatrixFour shrinking boundariesanimatedMedium
Rotate Image90° in place · transpose + reverseanimatedMedium
Set Matrix ZeroesMarkers in the first row/colanimatedMedium