HackerRank Day 9 Recursion 3 solution | 30 days of code

HackerRank Day 9 Recursion 3 solution – In this HackerRank Day 9 Recursion 3 30 days of code problem set, we need to develop a program that takes an integer input and then prints the factorial of that integer input on the output screen.

Objective
Today, we are learning about an algorithmic concept called recursion.

Function Description
Complete the factorial function in the editor below. Be sure to use recursion.

factorial has the following paramter:

• int n: an integer

Returns

• int: the factorial of n

Note: If you fail to use recursion or fail to name your recursive function factorial or Factorial, you will get a score of 0.

Input Format

A single integer, n (the argument to pass to factorial).

Constraints

• 2 <= n <= 12
• Your submission must contain a recursive function named factorial.

Recursion 3 problem solution in Python 2.

# Enter your code here. Read input from STDIN. Print output to STDOUT
def factorial(n):
    if n==0 or n==1:
        return 1
    else:
        return factorial(n-1)*n
print factorial(int(raw_input()))

Problem solution in Python 3.

#!/bin/python3

import math
import os
import random
import re
import sys

# Complete the factorial function below.
def factorial(n):

    if n == 1:
        return 1
    else:
        n = n * factorial(n-1)
    return n


if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    n = int(input())

    result = factorial(n)

    fptr.write(str(result) + 'n')

    fptr.close()

Problem solution in java.

import java.io.*;
import java.util.*;

public class Solution {

    public static int factorial(int n){
        return (n > 1) ? n * factorial(n-1) : 1;
    }
    
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        scan.close();
        System.out.println(factorial(n));
    }
}

Problem solution in c++.

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int factorial(int n){
    int r;
    if(n != 1){
        r = n * factorial(n-1);
    }
    else
        r = 1;
    return r;
}

int main() {
    int n;
    cin >> n;
    int r = factorial(n);
    cout << r << endl;
    return 0;
}

Problem solution in c.

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int factorial(int);
int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int n;
    scanf("%d",&n);
    printf("%d",factorial(n));
    return 0;
}

int factorial(int n)
    {
    if(n==0)
        return 1;
    else
        return n*factorial(n-1);
}

Problem solution in Javascript.

function processData(input) {
    //Enter your code here
    var N = parseInt(input),
        num = 1;
    
    function factorial(N){
        if (N > 1){
            num = num * N;
            factorial(N-1);
        }
    }
    factorial(N);
    console.log(num);
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});