Overview
Binary tree traversal: pre-order (root-left-right), in-order (left-root-right), post-order (left-right-root) teen recursive methods.
Analogy
Jaise family tree padhna—in-order ascending descendants deta hai, pre-order ancestors pehle, post-order children pehle.
Step-by-step
- Pre-order: node process karo→left→right
- In-order: left→node process karo→right
- Post-order: left→right→node process karo
- Saare methods mein None check base case
Visual
4
/ \
2 5
/ \
1 3
In-order: 1,2,3,4,5
Pre-order: 4,2,1,3,5
Post-order: 1,3,2,5,4
Common mistakes
- Teen traversal orders ka confusion
- None check base case bhool jana
Practice questions
- Stack se iterative in-order traversal implement karo
- Recursive aur iterative traversal compare karo