Introduction to Trees
A Tree is a non-linear data structure that represents hierarchical relationships. Unlike arrays or stacks, trees have a recursive structure: every node is itself the "root" of a smaller tree (subtree).
1. Real-World Intuition: The File System
Think of your computer's folders:
- The Root is the C: drive.
- Folders are internal nodes.
- Files are leaf nodes (they don't have children).
2. Curriculum in this Module
- Theory & Intuition (Current Page)
- Lesson: Tree Traversals (BFS vs DFS) - The core navigation patterns.
- Problem: Maximum Depth of Binary Tree - Basic recursive DFS.
- Problem: Validate Binary Search Tree - Mastering BST properties.
- Problem: Lowest Common Ancestor - Finding the shared parent.
- Curated Practice Problems - 10 essential challenges.
3. Tree Terminology Cheat Sheet
- Root: The top node.
- Leaf: A node with no children.
- Height: Number of edges from root to the furthest leaf.
- Binary Tree: Each node has at most 2 children.
- Binary Search Tree (BST): Left child < Parent < Right child.
Final Takeaway
90% of Tree problems are solved using Recursion. If you can solve a problem for a single node and its two children, you can solve it for the entire tree.