Sum Root to Leaf Numbers

Sum Root to Leaf Numbers

Total Accepted: 63531 Total Submissions: 202910 Difficulty: Medium

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.

 (E) Path Sum (H) Binary Tree Maximum Path Sum

 

/**
 * 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:
    void sumNumbers(TreeNode* root,int &curSum,int num){
        if(!root) return;
        num = num*10+root->val;
        if(root->left ==NULL && root->right ==NULL){
            curSum += num;
            return ;
        }
        sumNumbers(root->left,curSum,num);
        sumNumbers(root->right,curSum,num);
    }
    int sumNumbers(TreeNode* root) {
        int sum = 0;
        sumNumbers(root,sum,0);
        return sum;
    }
};