Home30 Days Of CodeHackerRank Day 9 : Recursion 3 30 days of code solution

# HackerRank Day 9 : Recursion 3 30 days of code solution

Today we are going to solve  Hackerrank Day 9 : Recursion 3 30 days of code solution  in C, C++ , Java , Python & Javascript.

## 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.

Sample Input

``3``

Sample Output

``6``

Explanation

Consider the following steps. After the recursive calls from step 1 to 3, results are accumulated from step 3 to 1.

1. factorial(3) = 3 x factorial(2) = 3 x 2 = 6
2. factorial(2) = 2 x factorial(2) = 2 x 1 = 2
3. factorial(1) = 1

## Recursion 3 HackerRank Solution in C

```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));
}
}```

## Recursion 3 HackerRank 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;
}```

## Recursion 3 HackerRank 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));
}
}```

## Recursion 3 HackerRank 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()```

## Recursion 3 HackerRank Solution in JavaScript

```function processData(input) {
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);
});```

30 Days of Code HackerRank Solutions List – Day 0 to Day 29

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