110702 Carmichael Numbers

import java.util.*;import static java.lang.Math.*;public class Main {private static boolean IsPrime(long number){long mid = (long)(sqrt((double)number));for (long i = 2; i <= mid; ++i){if ((number % i) == 0)return false;}return true;}private static long CarmichaelMod(long a, long powers, long number){if (powers == 1)return a % number;if (powers == 2)return (a * a) % number;long result = CarmichaelMod(a, powers/2, number);result = (result * result) % number;if ((powers % 2) != 0)result = (result * a) % number;return result;}private static boolean MeetCarmichaelRule(long number, long a){return CarmichaelMod(a, number, number) == a;}private static boolean IsCarmichaelNumber(long number){if (IsPrime(number))return false;for (long i = 2; i < number; ++i){if (!MeetCarmichaelRule(number, i))return false;}return true;}private static boolean IsCarmichaelNumber(HashSet<Long> allCarmichaelNumbers, long number){return allCarmichaelNumbers.contains(number);}private static HashSet<Long> GetAllCarmichaelNumbers(long limit){HashSet<Long> result = new HashSet<Long>();for (long i = 4; i < limit; ++i){if (IsCarmichaelNumber(i))result.add(i);}return result;}public static void main(String[] args) {HashSet<Long> allCarmichaelNumbers = GetAllCarmichaelNumbers(65000);    Scanner in = new Scanner(System.in);    while (true)    {    long number = in.nextLong();    if (number == 0)    return;    if (IsCarmichaelNumber(allCarmichaelNumbers, number))    System.out.println("The number " + number + " is a Carmichael number.");    else    System.out.println(number + " is normal.");    }}}