public static int compare(Node n1, Node n2) {
		int result = 0;
		int k1 = Integer.parseInt(n1.idString);
		int k2 = Integer.parseInt(n2.idString);
		if (c == 1) {
			return (k1 < k2)? -1 : 1;
		}
		if (c == 2) {
			int tmp = n1.name.compareTo(n2.name);
			if (tmp == 0) {
				return k1 < k2? -1 : 1;
			}else {
				return tmp;
			}
		}
		if (c == 3) {
			if (n1.score == n2.score) {
				return k1 < k2? -1 : 1;
			}else {
				return n1.score < n2.score? -1 : 1;
			}
		}
		return result;
	}