Find The Sum Of The Left Leaves Problem Statement

Given a binary tree with ‘root’, your task is to find and return the sum of all the left leaf nodes.

Example:

Input:

1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1

Output:

9

Explanation:

Node 4 and Node 5 are the left leaf nodes in the tree. Node 6 is a leaf node but not a left child. Therefore, the sum is 4 + 5 = 9.

Constraints:

• 1 ≤ T <= 10
• 1 ≤ N <= 1000
• Where ‘T’ is the number of test cases. ‘N’ is the number of nodes in the binary tree.
• Time Limit: 1 sec

Note:

You do not need to print anything; this has already been taken care of. Just implement the function and return the answer.