[LeetCode] Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \      \
        7    2      1

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
    bool getMax(int sum, TreeNode *node, int subSum)
    {
        if(!node) return false;
     subSum += node->val;
     if(!node->right && !node->left) return sum == subSum;
     if(getMax(sum, node->left, subSum)) return true;
     if(getMax(sum, node->right, subSum)) return true;
     return false;
    }
public:
    bool hasPathSum(TreeNode *root, int sum) 
    {
        return getMax(sum, root, 0);
    }
};