public static void print_queen(int size, int[] queens) {
		String[] str = new String[size];
		for (int i = 1; i <= size; i++) {
			int temp = queens[i];
			String s = "";
			for (int j = 0; j < size; j++) {
				if (j + 1 == temp) {
					s += "Q";
					continue;
				}
				s += ".";
			}
			str[i - 1] = s;
		}
		result.add(str);
	}