[LeetCode] Sum Root to Leaf Numbers（bfs）

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) {
        if(root==NULL)
            return 0;
        queue<TreeNode*> q;
        q.push(root);
        return bfs(q);
    }
private:
    int bfs(queue<TreeNode*> &q){
        TreeNode *p;
        int res = 0;
        while(!q.empty()){
            p = q.front();
            q.pop();
            if(p->left != NULL){
                p->left->val += (p->val * 10 );
                q.push(p->left);
            }
            if(p->right != NULL){
                p->right->val += (p->val * 10);
                q.push(p->right);
            }
            if(p->left==NULL && p->right==NULL){
               res += p->val;
            }
            
        }//end while
     return res;
    }
};