Question

In a binary search tree with the following elements: \( 10, -4, 15, 13, 20, 5, 16, 19 \), the number of edges from node 19 to the root is?

• A. 3
• B. 4
• C. 2
• D. 5

Hint:

When counting the number of edges from a node to the root in a binary search tree, simply trace the path from the node back to the root, counting each edge.

Answer 1

The Correct Option is B

Step 1: Visualizing the Binary Search Tree (BST).

The given elements are \( 10, -4, 15, 13, 20, 5, 16, 19 \). We can build the BST as follows:


1. \( 10 \) is the root.
2. \( -4 \) goes to the left of \( 10 \).
3. \( 15 \) goes to the right of \( 10 \).
4. \( 13 \) goes to the left of \( 15 \).
5. \( 20 \) goes to the right of \( 15 \).
6. \( 5 \) goes to the right of \( -4 \).
7. \( 16 \) goes to the left of \( 20 \).
8. \( 19 \) goes to the right of \( 16 \).


Step 2: Traversing from node 19 to the root.


- The path from node 19 to the root is: \( 19 \to 16 \to 20 \to 15 \to 10 \).
- Therefore, the number of edges is 4.


Thus, the correct answer is \( 4 \).