LeetCode 404. 左叶子之和

题目链接：https://leetcode-cn.com/problems/sum-of-left-leaves/

计算给定二叉树的所有左叶子之和。

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     struct TreeNode *left;
 6  *     struct TreeNode *right;
 7  * };
 8  */
 9 
10 int sumOfLeftLeaves(struct TreeNode* root){
11     if(root==NULL) return 0;
12     if(root->left!=NULL&&root->left->left==NULL&&root->left->right==NULL) return root->left->val+sumOfLeftLeaves(root->right);
13     return sumOfLeftLeaves(root->left)+sumOfLeftLeaves(root->right);
14 }