Extra Long Factorials Hackerrank Solution

The factorial of a number is defined as the product of all natural numbers up to that number. For example, factorial of 5 or 5! is 1 x 2 x 3 x 4 x 5 = 120.

Extra long factorials are factorials of numbers greater than 20. They can be very big with an order of magnitude greater than 2^64 which can not be stored even in long long data types in C or C++. Modern languages like Python and JavaScript can easily store them.

Python Code for Extra Long Factorials Hackerrank Solution

def extraLongFactorials(n):
    # Write your code here
    fact = 1
    for num in range(2, n+1):
        fact *= num
    print(fact)

if __name__ == '__main__':
    n = int(input().strip())

    extraLongFactorials(n)

Input

Output

15511210043330985984000000

JS Code for Extra Long Factorials Hackerrank Solution

Javascript output large numbers in scientific notation. We will get the output of 25! as 1.5511210043330984e+25. To avoid this we have to use BigInt.

function extraLongFactorials(n) {
    // Write your code here
    var fact = BigInt(1)
    for(var num=2n; num<=n; num++){
        fact = fact * num
    }
    console.log(fact.toString())
}

function main() {
    const n = parseInt(readLine().trim(), 10);

    extraLongFactorials(n);
}