Recursive DFS + Iterative DFS using Stack

Core Skill

• Understand traversal orders
• Convert recursion ⇄ stack

Problems

• Binary Tree Inorder Traversal
• Binary Tree Preorder Traversal
• Binary Tree Postorder Traversal

Patterns

• Recursive DFS
• Iterative using stack

Why this matters

• Foundation for all tree problems
• Teaches how recursion maps to stack