codewars066 - Large Factorial

Instructions

https://www.codewars.com/kata/557f6437bf8dcdd135000010/train/java

Solution:

import java.math.BigInteger;

public class Kata
{

  public static String Factorial(int n) {
	  if(n < 0){
		  return null;
	  }
	  if(n == 0 || n == 1){
		  return "1";
	  }
	  BigInteger product = BigInteger.ONE;
	 for(int i = 2; i <= n; i++){
		 product = product.multiply(new BigInteger(String.valueOf(i)));
	 }
    return product.toString();
  }

}

Sample Test:

https://www.codewars.com/kata/557f6437bf8dcdd135000010/train/java