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# Deepest Leaves Sum

Given the root of a binary tree, return the sum of values of its deepest leaves.

Example 1:

Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
Output: 15

Example 2:

Input: root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
Output: 19

Constraints:

• The number of nodes in the tree is in the range [1, 104].

• 1 <= Node.val <= 100

Solution:

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode() {}
*     TreeNode(int val) { this.val = val; }
*     TreeNode(int val, TreeNode left, TreeNode right) {
*         this.val = val;
*         this.left = left;
*         this.right = right;
*     }
* }
*/
class Solution {
public int deepestLeavesSum(TreeNode root) {
if(root==null) return 0;
q.offer(root);
int sum=0;
while(!q.isEmpty())
{
int size = q.size();
sum=0; //reset sum for every level
while(size-- >0)
{
TreeNode node = q.poll();
sum+=node.val;
if(node.left!=null) q.offer(node.left);
if(node.right!=null) q.offer(node.right);
}
}
return sum;
}
}