leetcode---Sum Root to Leaf Numbers---树的深度遍历

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