- 递归的同时计算就可以了
class Solution {
public:
int sumNumbers(TreeNode* root) {
return getSum(root, 0);
}
int getSum(TreeNode * root, int val){
if(!root)
return 0;
if(!root->left && !root->right) //注意只有叶子节点才会有值
return val * 10 + root->val;
return getSum(root->left, val * 10 + root->val) +
getSum(root->right, val * 10 + root->val);
}
};