Расстановка фишек

public class FindSequenceBySum
{
	static int n = 5;
	static int m = 2;
	static int mm = 0;
	static char[] a = new char[n + 1];
	static int num = 0;

	public static void rec(int idx)
	{
		if (idx == n)
		{
			num++;
			for (int i = 0; i < idx; i++)
			{
				System.out.print(a[i]);
			}

			System.out.println();
			return;
		}


		if (idx == 0 || (a[idx - 1] != '*' && mm != m))
		{
			a[idx] = '*';
			mm++;
			rec(idx + 1);
			mm--;
		}

		a[idx] = '.';
		rec(idx + 1);
	}

	public static void main(String[] args)
	{
		rec(0);
	}

}