Module Review: Trees
You’ve moved from linear lists to hierarchical power.
1. Key Takeaways
- Structure: Recursive definition (Node + Left + Right).
- BST: Sorted property enables O(log N) search.
- Traversal:
- DFS: Stack (Recursion). Pre/In/Post.
- BFS: Queue. Level Order.
- LCA: The meeting point of two nodes.
2. Cheat Sheet
| Algorithm | Time Complexity | Space Complexity | Use Case |
|---|---|---|---|
| DFS (Pre/In/Post) | O(N) | O(H) | Exhaustive search, Serializing. |
| BFS (Level Order) | O(N) | O(W) (Width) | Shortest Path (Unweighted), Layer-by-layer. |
| BST Search | O(log N) / O(N) | O(H) | Database Indexing, Sets. |
| LCA | O(N) | O(H) | Genealogy, Routing. |
3. Interactive Flashcards
What traversal yields sorted order in a BST?
Inorder Traversal (Left → Root → Right).
What data structure is used for BFS?
Queue.
What is the worst-case height of a BST?
O(N) (Skewed / Linked List). Balanced is O(log N).
Where is the Lowest Common Ancestor logic derived from?
Postorder Traversal (Bottom-Up).
4. Next Steps
Next Module: Heaps - Priority Queues and Sorting.
DSA Glossary
Module Review: Trees
[!NOTE] This module explores the core principles of Module Review: Trees, deriving solutions from first principles and hardware constraints to build world-class, production-ready expertise.
1. Practice in the Vault
Looking to solidify your understanding? Head over to the Problem Vault to solve curated problems related to this module with detailed walkthroughs and optimal solutions.