The preorder traversal of a Binary Search Tree (BST) is (10, 5, 1, 7, 40, 50).…
2023
The preorder traversal of a Binary Search Tree (BST) is (10, 5, 1, 7, 40, 50). What is its postorder traversal?
- A.
(1, 5, 7, 10, 40, 50)
- B.
(50, 40, 10, 7, 5, 1)
- C.
(1, 7, 5, 10, 40, 50)
- D.
None of these
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Correct answer: D
Correct answer: None of these
Preorder traversal follows Root → Left → Right. So the first value, 10, is the root.
Values smaller than 10 form the left subtree: 5, 1, 7. This subtree has root 5, with 1 on the left and 7 on the right. Its postorder is 1, 7, 5.
Values greater than 10 form the right subtree: 40, 50. This subtree has root 40, with 50 on the right. Its postorder is 50, 40.
Combine left postorder, right postorder, and root: 1, 7, 5, 50, 40, 10.
The obtained sequence is not present in the listed numerical options, so None of these is correct.