Code, learned like a story.
Every hard idea in CS — recursion, graphs, hashing, dynamic programming — is taught as a six-minute animated story you'll actually remember a week later. Not slides. Not lectures. Stories.
Table of contents
01The Postman of the Sorted Kingdombinary search ✓
02The Wedding Planner's Ledgerhash maps ✓
03The Courier's Shortest Routereading now
04The Time-Travelling Accountantdynamic prog.
Each story ends inrunnable code + a mock question
You don't forget a story. You forget a slide.
Memory is built around narrative. Ask anyone what Binary Search is, and they'll quote a textbook. Ask them about the postman of the Sorted Kingdom hunting for house number 73, and they'll tell you the whole algorithm — including the edge case where lo crosses hi. That's the bet CodeStory is built on, and that's what every lesson on this page is.
60+ stories. 500+ concepts. One curriculum.
A sample of the catalog. Each story ends with code, a real-interview problem, and an AI mock asking you to explain it out loud.
Anatomy of a story-lesson.
Cold open
A character has a problem. No code. No keywords. Just a situation you've been in.
The idea, animated
We show the algorithm visually — pointers move, halves get tossed, the search shrinks. The idea before the syntax.
Code, line-by-line
Now the code appears, and each line lights up as the animation runs. You see what each line is doing, not just what it says.
Defend it out loud
An AI interviewer asks you to explain the idea. If you can't, you don't pass. That's the bar a real interview will hold you to anyway.
What we cover.
Arrays & Strings
- Two pointers
- Sliding window
- Prefix sums
- Kadane's
Searching & Sorting
- Binary search
- Quicksort
- Mergesort
- Heap sort
Hashing
- Hash maps
- Hash sets
- Collision handling
- LRU caches
Recursion & Backtracking
- Towers of Hanoi
- N-Queens
- Subsets & permutations
- Sudoku solver
Trees
- BST
- Traversals
- Diameter
- Tries
Graphs
- BFS / DFS
- Dijkstra
- Topological sort
- Union-find
Dynamic Programming
- Knapsack
- LIS
- LCS
- Matrix-chain
System Design (intro)
- Rate limiter
- URL shortener
- News-feed
- Chat
You can watch every playlist, take perfect notes, and still freeze when someone asks you to explain recursion. Stories fix the explaining — you watch Hanoi happen, then say it back in your own words.



