[Solved] Consider the following iterative postorder traversal code to compute the diameter of a... Given the tree: 1 / \ 2 3 / 4 What is the final value of the variable diameter after the function completes? | Tree: Depth-First Search

Tree: Depth-First Search - Diameter of Binary Tree

Consider the following iterative postorder traversal code to compute the diameter of a binary tree. Given the tree: 1 / \ 2 3 / 4 What is the final value of the variable diameter after the function completes?

A2

B4

C1

D3

Step-by-Step Solution

Solution:

Step 1: Trace heights and diameter updates for each node.
Node 4: height=1, diameter=0; Node 2: left=1 (node4), right=0, diameter=max(0,1)=1; Node 3: height=1, diameter=1; Node 1: left=2 (node2), right=1 (node3), diameter=max(1,2+1=3)=3.
Step 2: Verify final diameter value returned.
The diameter is the maximum sum of left and right heights at any node, which is 3 edges, so the longest path length is 3 edges.
Final Answer:
Option D -> Option D
Quick Check:
Longest path is from node 4 to node 3 with length 3 edges [OK]

Quick Trick: Diameter counts edges, not nodes [OK]

Common Mistakes:

MISTAKES

Confusing diameter as number of nodes
Off-by-one in height calculation
Missing right subtree height

Trap Explanation:

PITFALL

Counting nodes instead of edges leads to off-by-one errors in diameter value.

Interviewer Note:

CONTEXT

Checks candidate's ability to mentally execute iterative postorder and understand diameter definition.

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More Tree: Depth-First Search Quizzes

Given the tree: 1 / \ 2 3 / 4 What is the final value of the variable diameter after the function completes?

Step 1: Trace heights and diameter updates for each node.

Step 2: Verify final diameter value returned.

Final Answer:

Quick Check:

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