Pre-Order Traversal

overview

Remember these Terms

• Pre-order (NLR): Visit node, then left, then right.
• Tree: Hierarchical structure of connected nodes.
• Node: Holds a value and child links.
• Root: The topmost node in the tree.
• Left/Right child: Immediate descendants of a node.
• DFS: Depth-first family; pre-order is one.
• Recursion: Function calls itself to traverse.
• Stack: Stores nodes for iterative traversal.
• Visit/Process: Do work on the current node.
• Time/Space: O(n) time, O(h) extra space.