LeetCode Sum Root to Leaf Numbers

Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

An example is the root-to-leaf path 1->2->3 which represents the number 123.

Find the total sum of all root-to-leaf numbers.

For example,

    1   / \  2   3

The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.

Return the sum = 12 + 13 = 25.

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:int sumNumbers(TreeNode *root) {int allsum = 0, cursum = 0;if (root == NULL)return allsum;vector<TreeNode *> ivec;calsum(root, ivec, cursum, allsum);return allsum;}void calsum(TreeNode *root, vector<TreeNode *> &ivec, int &cursum, int &allsum) {cursum = cursum * 10 + root->val;ivec.push_back(root);if (root->left == NULL && root->right == NULL)  allsum += cursum;if (root->left)calsum(root->left, ivec, cursum, allsum);if (root->right)calsum(root->right, ivec, cursum, allsum); ivec.pop_back();cursum = (cursum - root->val) / 10;return;}};