STACKSIM · DSA & SYSTEM DESIGN
Learn software engineering
by simulation.
Visualize algorithms step-by-step, trace JavaScript execution, and experiment with system design in your browser.
Learn by doing No setup needed Go at your pace
SLIDING WINDOWJavaScript
0a
1b
2cL
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current window
WINDOW
c a bMAX LENGTH
3TIME
O(n)A little less abstract.
A lot more intuitive.
A lot more intuitive.
5learning levels
31active topics
51interactive problems
0 / 51problems passed
Your learning path
Start with the foundations. Build your way up.
LEVEL 1
Foundations
Build your algorithmic intuition.
9 topics · 37 problems
Ready when you are
LEVEL 2
Core Data Structures
Think in links, stacks, and recursive calls.
7 topics · 17 problems
Ready when you are
LEVEL 3
Advanced Data Structures
Organize data for more powerful operations.
5 topics · 12 problems
Ready when you are
LEVEL 4
Graph Algorithms
Explore connections and find your way.
6 topics · 8 problems
Ready when you are
LEVEL 5
Advanced Problem Solving
Combine patterns to solve harder problems.
4 topics · 10 problems
Ready when you are
A great place to start
Small problems. Big moments of understanding.
Think in patterns
Recognize the clue. Choose the technique.
A NEW LEARNING TRACK
Think beyond a single algorithm.
Route requests, change backend capacity, and watch a distributed system respond.
FROM UNDERSTANDING TO PRACTICE
Your next “aha” moment is one run away.
Write JavaScript, test your ideas, and learn from every result.
DESIGN FROM THE INSIDE OUT
Explore the course →Understand Low-Level Design
66 lessons. OOP, SOLID, UML, all 23 classic patterns, and three systems you can explore.