Tree Traversal Postorder Left Right Root in DSA Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the order of visiting nodes in Postorder Tree Traversal?

In Postorder traversal, nodes are visited in the order: Left subtree, Right subtree, then Root node.

intermediate

Why is Postorder traversal useful in deleting a tree?

Postorder traversal visits children before the parent, so it safely deletes all child nodes before deleting the parent node.

beginner

Given a binary tree, what will be the Postorder traversal output for this tree?<br>Root: 1<br>Left child: 2<br>Right child: 3

The Postorder traversal visits Left (2), Right (3), then Root (1). So output is: 2 -> 3 -> 1

beginner

Show the Go function signature for a recursive Postorder traversal of a binary tree node.

func postorderTraversal(root *TreeNode) { // implementation }

beginner

What is the main difference between Inorder and Postorder traversal?

Inorder visits nodes in Left, Root, Right order, while Postorder visits nodes in Left, Right, Root order.

In Postorder traversal, which node is visited last?

A Right child

B Left child

C Root node

D None of the above

Postorder visits Left subtree, then Right subtree, and finally the Root node.

What is the Postorder traversal of a tree with root 5, left child 3, and right child 7?

A 3 -> 7 -> 5

B 3 -> 5 -> 7

C 7 -> 3 -> 5

D 5 -> 3 -> 7

Postorder visits Left (3), Right (7), then Root (5).

Which traversal is best suited for deleting all nodes in a tree safely?

A Preorder

B Postorder

C Inorder

D Level order

Postorder visits children before the parent, so it deletes safely.

In Postorder traversal, what is the first subtree visited?

A Left subtree

B Root node

C Right subtree

D None

Postorder starts with the Left subtree.

Which of these is the correct Postorder traversal output for this tree?<br>Root: 10<br>Left child: 5<br>Right child: 15

A 5 -> 10 -> 15

B 10 -> 5 -> 15

C 15 -> 10 -> 5

D 5 -> 15 -> 10

Postorder visits Left (5), Right (15), then Root (10).

Explain the steps of Postorder traversal on a binary tree.

Think about visiting children before the parent.

Describe a real-life scenario where Postorder traversal is useful.

Consider tasks that require finishing all parts before the whole.