Extra Long Factorials - HackerRank Solutions

The factorial of the integer n, written n!, is defined as:

n!=n×(n-1)×(n-2)×···×3×2×1

Calculate and print the factorial of a given integer.

For example, if n=30, we calculate 30×29×28×···×2×1 and get .

265252859812191058636308480000000.

Function Description

Complete the extraLongFactorials function in the editor below. It should print the result and return.

extraLongFactorials has the following parameter(s):

• n: an integer

Note: Factorials of n > 20 can't be stored even in a 64-bit long long variable. Big integers must be used for such calculations. Languages like Java, Python, Ruby etc. can handle big integers, but we need to write additional code in C/C++ to handle huge values.

We recommend solving this challenge using BigIntegers.

Input Format

Input consists of a single integer n.

Constraints

1≤n≤100

Output Format

Print the factorial of n.

Sample Input

25

Sample Output

155112100433309859884000000

Explanation

25! = 25×24×23×···×3×2×1

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Extra Long Factorials - HackerRank Solutions 

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;
public class Solution {
    // Complete the extraLongFactorials function below.
    static void extraLongFactorials(int n) {
        BigInteger fac=new BigInteger("1");
        for(int i=1;i<=n;i++)
            fac=fac.multiply(BigInteger.valueOf(i));
        System.out.println(fac);
    }
    private static final Scanner scanner = new Scanner(System.in);
    public static void main(String[] args) {
        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
        extraLongFactorials(n);
        scanner.close();
    }
}