POJ 3537 crosses and crosses SG functions

In 1*n's lattice, the x is rotated, the 3 consecutive X wins, and after the position x is divided into 2 parts: start to I-3 and i+2 to the end.

Package FD;

Import Java.lang.reflect.Array;
Import Java.util.Arrays;
Import Java.util.HashSet;
Import Java.util.Scanner;
Import Java.util.Set;

public class Main {

	static int[] sg = new int[2222];
	static int SG (int n) {
		if (n <= 0) {
			return 0;
		}
		if (n <= 3) {
			return 1;
		}
		if (sg[n]! =-1) {
			return sg[n];
		}
		set<integer> s = new hashset<integer> ();
		for (int i = 1; i<= n; i++) {
			s.add (SG (i-3) ^SG (n-i-2));
		}
		int res = 0;
		while (S.contains (res)) {
			res++;
		}
		return Sg[n] = res;
	}
	public static void Main (string[] args) {
		//TODO auto-generated method stub
		Scanner sc = new Scanner (system.in);
		Arrays.fill (SG,-1);
		while (Sc.hasnext ()) {
			int n = sc.nextint ();
			System.out.println (SG (n) = = 0? 2:1);}}}