【同113】LeetCode 129. Sum Root to Leaf Numbers

LeetCode 129. Sum Root to Leaf Numbers

Solution1：我的答案
二叉树路径和问题，类似113

/**
 * 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 sumNumbers(TreeNode* root) {
        if (!root) return 0;
        int sum = 0;
        vector<int> temp;
        my_sum(root, temp, sum);
        return sum;
    }

    void my_sum(TreeNode* root, vector<int>& temp, int &sum) {
        if (!root) return;
        temp.push_back(root->val);
        if (!root->left && !root->right) {
            int temp_sum = 0;
            for (int i = 0; i < temp.size(); i++)
                temp_sum = temp_sum * 10 + temp[i];
            sum += temp_sum;
        }
        my_sum(root->left, temp, sum);
        my_sum(root->right, temp, sum);
        temp.pop_back();
    }
};