[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.

Analysis: It's the same question as get Binary Tree Paths

/**
 * 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 {
/**
 * 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 {
    vector<string> getAllPaths(TreeNode * node)
    {
        vector<string> res;
        if(!node) return res;
        string cur = to_string(node->val);
        if(!node->left && !node->right) res.push_back(cur);
        
        if(node->left)
        {
            vector<string> left = getAllPaths(node->left);
            for(auto e :left) res.push_back(cur+e);
            
        }
        if(node->right)
        {
            vector<string> right = getAllPaths(node->right);
            for(auto e :right) res.push_back(cur+e);
        }    
        return res;
    }
public:
    int sumNumbers(TreeNode* root) {
        vector<string> paths = getAllPaths(root);
        int res = 0;
        for(auto e:paths) res += stoi(e);
        return res;
    }
};