[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 {
public:
    int target = 0;
    bool search(TreeNode *cur, int curSum)
    {
        if(cur == NULL) return false;
        curSum += cur -> val;
        if(curSum == target && cur -> left == NULL && cur -> right == NULL) return true;
        return search(cur -> left, curSum) || search(cur -> right, curSum);
    }
    bool hasPathSum(TreeNode *root, int sum) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(root == NULL) return false;
        target = sum;
        return search(root, 0);
    }
};