LeetCode - Refresh - Path Sum

Recursive.

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     bool getSum(TreeNode *root, int sum, int target) {
13         if (!root) return false;
14         sum += root->val;
15         if (!root->left && !root->right && sum == target) return true;
16         return getSum(root->left, sum, target) || getSum(root->right, sum, target);
17     }
18     bool hasPathSum(TreeNode *root, int sum) {
19         return getSum(root, 0, sum);
20     }
21 };