C++
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int sumOfLeftLeaves(TreeNode* root) {
if(root==NULL) return 0;
else if(root->left!=NULL&&root->left->left==NULL&&root->left->right==NULL)
{
return sumOfLeftLeaves(root->left)+sumOfLeftLeaves(root->right)+root->left->val;
}
else
return sumOfLeftLeaves(root->left)+sumOfLeftLeaves(root->right)+0;
}
};
Java
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int sumOfLeftLeaves(TreeNode root) {
if(root==null) return 0;
else if(root.left!=null&&root.left.left==null&&root.left.right==null)
{
return sumOfLeftLeaves(root.left)+sumOfLeftLeaves(root.right)+root.left.val;
}
else
return sumOfLeftLeaves(root.left)+sumOfLeftLeaves(root.right)+0;
}
}
Javascript
/**
* Definition for a binary tree node.
* function TreeNode(val) {
* this.val = val;
* this.left = this.right = null;
* }
*/
/**
* @param {TreeNode} root
* @return {number}
*/
var sumOfLeftLeaves = function(root) {
if(root===null) return 0;
else if(root.left!==null&&root.left.left===null&&root.left.right===null)
{
return sumOfLeftLeaves(root.left)+sumOfLeftLeaves(root.right)+root.left.val;
}
else
return sumOfLeftLeaves(root.left)+sumOfLeftLeaves(root.right)+0;
};
最优解，一样
