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:
bool hasPathSum(TreeNode* root, int sum) {
if(root==NULL) return false;
if(root->left ==NULL && root->right == NULL) return root->val==sum;
if(hasPathSum(root->left,sum-root->val))return true;
if(hasPathSum(root->right,sum-root->val))return true;
return false;
}
};