Sum of Left Leaf Nodes

       
        
        Given a Binary Tree of size N. Find the sum of all the leaf nodes that are left child of their parent 
        of the given binary tree.


        Example 1:

        Input:
             1
           /   \
          2     3
        Output: 2

        Example 2:

        Input:
               1
             /  \
            2    3
           /  \    \
          4    5     8 
         /  \       /  \
        7    2      6    9
        Output: 13
        Explanation:
        sum = 6 + 7 = 13

        
        

        Code
        
        int leftLeavesSum(Node *root)
        {
           if(root==NULL)
            return 0;
     
           if((root->left)&&(root->left->left==0)&&(root->left->right==0))
             return root->left->data+leftLeavesSum(root->right);
      
            return leftLeavesSum(root->left)+leftLeavesSum(root->right);
        }