Sum Root to Leaf Numbers 根节点到叶子组成数的和

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 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) {                return solve(root,0);    }        int solve(TreeNode *root,int sum)    {        if(root==NULL)        {            return 0;        }        if(root->left==NULL&&root->right==NULL)        {           return sum*10+root->val;        }        return solve(root->left,sum*10+root->val)+solve(root->right,sum*10+root->val);    }};