15 patterns. zero memorizing.
Algorithms you can watch move.
Every interview pattern, explained with a one-minute animation and a visualizer you can poke, pause and step through.
sliding windowstep 9 / 25
window"bc"
seen{b,c}
best so far3
Yes, it repeats. Move the left edge past ‘a’.
Pick a pattern
All 15 lessons live →FOUNDATIONS
Start here. Arrays, pointers and windows.01–05STRUCTURES & RECURSION
Lists, trees and trying every option.06–10ADVANCED
Graphs, dynamic programming and greedy choices.11–1501 WATCH
A 60-second explainer
Intuition first. The animation shows why it works before any code appears.
02 PLAY
Step through it
Your input, your pace. Forward and back, one line at a time.
03 PRACTISE
Solve the classics
A short, ordered list of real interview problems, with progress saved.