1.                                                    Between Two Sets
  2.  
  3. There will be two arrays of integers. Determine all integers that satisfy the following two conditions:
  4.  
  5. The elements of the first array are all factors of the integer being considered
  6. The integer being considered is a factor of all elements of the second array
  7. These numbers are referred to as being between the two arrays. Determine how many such numbers exist.
  8.  
  9.  
  10.  
  11.  
  12.  
  13.  
  14. static int getGCD(int n1, int n2) {
  15.     if (n2 == 0) {
  16.       return n1;
  17.     }
  18.     return getGCD(n2, n1 % n2);
  19.   }
  20.  
  21.  static int getLCM(int n1, int n2) {
  22.     if (n1 == 0 || n2 == 0)
  23.       return 0;
  24.     else {
  25.       int gcd = getGCD(n1, n2);
  26.       return Math.abs(n1 * n2) / gcd;
  27.     }
  28.   }
  29.  
  30.   public static int getTotalX(List<Integer> a, List<Integer> b) {
  31.     int result = 0;
  32.  
  33.     // Get LCM of all elements of a
  34.     int lcm = a.get(0);
  35.     for (Integer integer : a) {
  36.       lcm = getLCM(lcm, integer);
  37.     }
  38.  
  39.     // Get GCD of all elements of b
  40.     int gcd = b.get(0);
  41.     for (Integer integer : b) {
  42.       gcd = getGCD(gcd, integer);
  43.     }
  44.  
  45.     // Count multiples of lcm that divide the gcd
  46.     int multiple = 0;
  47.     while (multiple <= gcd) {
  48.       multiple += lcm;
  49.  
  50.       if (gcd % multiple == 0)
  51.         result++;
  52.     }
  53.  
  54.     return result;
  55.   }