Hackerrank Java Primality Test Solution

A prime number is a natural number greater than  whose only positive divisors are  and itself. For example, the first six prime numbers are , , , , , and .

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

Input Format

A single line containing an integer,  (the number to be checked).

Constraints

• contains at most  digits.

Output Format

If  is a prime number, print prime; otherwise, print not prime.

Sample Input

13

Sample Output

prime

Explanation

The only positive divisors of  are  and , so we print prime.

Solution in java8

Approach 1.

import java.util.Scanner;

public class Solution
{
    public static void main(String[] args)
    {
        try (Scanner scanner = new Scanner(System.in);)
        {
            System.out.println(scanner.nextBigInteger().isProbablePrime(100) ? "prime" : "not prime");
        }
    }
}

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Approach 2.

import java.util.Scanner;
import java.math.BigInteger;

public class Solution {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        BigInteger n = scan.nextBigInteger();
        scan.close();
        System.out.println(n.isProbablePrime(10) ? "prime" : "not prime");
    }
}

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Approach 3.

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

   public static void main(String[] args) {
      Scanner in = new Scanner(System.in);
      BigInteger n = in.nextBigInteger();
      in.close();
      // Write your code here.
       boolean b=n.isProbablePrime(1);
      if(b){System.out.print("prime");}else{System.out.print("not prime");}
   }
}

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