Euler Problem 47 solution

Time (s): ~0.067

package margusmartseppcode.From_40_to_49;

public class Problem_47 {
 static int unique_factors(int num, int[] primes, int[] factors) {
  int max = (int) Math.sqrt(num);

  for (int i = 0; primes[i] <= max; i++)
   if ((num % primes[i]) == 0) {
    do {
     num /= primes[i];
    } while ((num % primes[i]) == 0);

    return num == 1 ? 1 : factors[num] + 1;
   }

  return 0;
 }

 // creates primes and factors on fly
 public static void main(String[] args) {
  int n = 0, ps = 1, max = 200000;
  int primes[] = new int[max], factors[] = new int[max];

  for (n = 3, primes[0] = 2; n < max; n++)
   if ((factors[n] = unique_factors(n, primes, factors)) == 0) {
    factors[n] = 1;
    primes[ps++] = n;
   } else if ((factors[n] == 4) && (factors[n - 1] == 4)
     && (factors[n - 2] == 4) && (factors[n - 3] == 4))
    break;

  System.out.println(n - 3);
 }
}