Method isPermutation

output/java_guava/1.4.18/Collections2.java:670–677

Returns true if the second list is a permutation of the first.

(List<?> first, List<?> second)

   */

  private static boolean isPermutation(List<?> first, List<?> second) {
    if (first.size() != second.size()) {
      return false;
    }
    Multiset<?> firstMultiset = HashMultiset.create(first);
    Multiset<?> secondMultiset = HashMultiset.create(second);
    return firstMultiset.equals(secondMultiset);
  }

  private static boolean isPositiveInt(long n) {
    return n >= 0 && n <= Integer.MAX_VALUE;