public boolean hasPathSum(TreeNode root, int sum) {
        if(root == null)
        	return false;
        else if( root.left == null && root.right == null && root.val == sum){
    		return true;
    	}
    	else
    		return hasPathSum(root.left,sum - root.val) ||hasPathSum(root.right, sum - root.val);
    }