/* Permutable Prime version 1.0 A permutable prime is a prime number of two or more digits that remains prime with every possible rearrangement of the digits. For example: Input: 79 Output: true (79 and 97 are both primes) Input: 127 Output: false Input: 337 Output: true (337, 373 and 733 are primes) Write a program to check if the user input is a permutable prime or not. */ import java.util.*; public class PermutablePrime { private static boolean isPrime(int num) { int count = 0; for (int i = 1; i <= num; i++) { if (num % i == 0) { ++count; } } if (count == 2) { return true; } else { return false; } } private static ArrayList permutations(int num) { String val = String.valueOf(num); ArrayList al = new ArrayList<>(); for (int i = 0; i < val.length() - 1; i++) { String temp = val.substring(i + 1); temp = temp + val.substring(0, i + 1); al.add(temp); temp = null; } return al; } private static ArrayList checkAllpermutations(ArrayList al) { ArrayList check = new ArrayList<>(); for (String checkPrime : al) { boolean b = false; b = isPrime(Integer.parseInt(checkPrime)); if (b == false) { break; } else { check.add(checkPrime); } } return check; } public static void main(String[] args) { Scanner sc = new Scanner(System.in); int num = sc.nextInt(); ArrayList al = permutations(num); ArrayList afterCheck = checkAllpermutations(al); System.out.println("Input : " + num); if (isPrime(num) && al.size()== afterCheck.size()) { System.out.print("Output : true (" + num + " "); for (String prime : afterCheck) { System.out.print(prime + " "); } System.out.print(") are primes"); } else { System.out.println("false"); } sc.close(); } }

Permutable Prime ::