HackerRank: Java Primality Test

A prime number is a natural number greater than 1 whose only positive divisors are 1 and itself. For example, the first six prime numbers are 2, 3, 5, 7, 11, and 13.

Given a large integer, n, use the Java BigInteger class' isProbablePrime method to determine and print whether it's prime or not prime.

Sample Input

13

Sample Output

prime

Java Code

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.math.BigInteger;

public class javaPrimalityTest {

    public static void main(String[] args) throws IOException {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        String n = bufferedReader.readLine();

        BigInteger m = new BigInteger(n);

       

        int rnd= (int)((Math.random()*100));

        boolean isPrime= m.isProbablePrime(rnd);

       

        if(isPrime)

            System.out.println("prime");

        else

            System.out.println("not prime");

        bufferedReader.close();

    }

}

Note: Comment if you want Explanation.