Leetcode 129 Solution

This article provides solution to leetcode question 129 (sum-root-to-leaf-numbers)
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https://leetcode.com/problems/sum-root-to-leaf-numbers

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 {
public:
    int sumNumbers(TreeNode* root, int curr) {
        if (root == NULL)
            return 0;

        int sum = 0;

        if (root->left == NULL && root->right == NULL)
        {
            return curr * 10 + root->val;
        }

        if (root->left)
            sum += sumNumbers(root->left, curr * 10 + root->val);

        if (root->right)
            sum += sumNumbers(root->right, curr * 10 + root->val);

        return sum;
    }

    int sumNumbers(TreeNode* root) {
        return sumNumbers(root, 0);
    }
};