Find the sum of all left leaves in a given binary tree.
Example:
3
/
9 20
/
15 7
There are two left leaves in the binary tree, with values 9 and 15 respectively. Return 24.
1 class Solution { 2 3 public int sumOfLeftLeaves(TreeNode root) { 4 if(root==null) return 0; 5 int sum = 0; 6 if(root.left!=null){ 7 if(root.left.left==null && root.left.right==null) sum +=root.left.val; 8 else sum+=sumOfLeftLeaves(root.left); 9 } 10 sum+=sumOfLeftLeaves(root.right); 11 return sum; 12 13 } 14 15 }