Sum of Leaf Nodes of Binary Tree.

Java Implementation of finding sum of leaf nodes in a binary tree iteratively.

import java.util.LinkedList;
import java.util.Queue;

class Solution
{
    static class TreeNode{
        int data;
        TreeNode left,right;
        TreeNode(int data)
        {
            this.data=data;
        }
    }
    static int SumOfLeafNodes(TreeNode root)
    {
        Queue<TreeNode> queue=new LinkedList<>();
        queue.add(root);
        int sum=0;
        while(!queue.isEmpty())
        {
            TreeNode temp=queue.poll();
            if(temp.left!=null)
                queue.add(temp.left);
            if(temp.right!=null)
                queue.add(temp.right);
            if(temp.left==null && temp.right==null)
                sum=sum+temp.data;
        }
        return sum;
    }
     public static void main(String[] args)
    {
        TreeNode root=new TreeNode(1);
        root.left=new TreeNode(2);
        root.right=new TreeNode(3);
        root.left.left=new TreeNode(4);
        root.left.right=new TreeNode(7);
        
        int sum=SumOfLeafNodes(root);
        System.out.println(sum);
         
    }
    }

Output: 14

Time Complexity- O(n)

Space Complexity- O(n)

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