Explain Tree Traversals: Inorder, Preorder, Postorder, Level Order.

Difficulty: 5/10

binary tree traversal, recursive vs iterative, breadth-first traversal

Tree Traversals

Tree traversal means visiting every node according to a defined order. Inorder visits Left, Root, Right and is especially important for BSTs because it produces sorted values. Preorder visits Root, Left, Right and is useful for serialization or copying tree structure. Postorder visits Left, Right, Root and is useful when children must be processed before their parent. Level order visits nodes level by level using a queue.

javascript

1
Inorder: L -> N -> R
2
Preorder: N -> L -> R
3
Postorder: L -> R -> N
4
Level Order: breadth-first traversal using a queue
5
DFS traversals use recursion or an explicit stack.
6
Traversal time is O(n) because every node is visited once.

Scenario Questions

0-2 years experience

Follow-up Questions