hacker-rank-30days-9.js

// problem

Objective
Today, we are learning about an algorithmic concept called recursion. Check out the Tutorial tab for learning materials and an instructional video.

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

Input Format

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

Constraints

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.




// solution => all tests are passed 

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', function(inputStdin) {
    inputString += inputStdin;
});

process.stdin.on('end', function() {
    inputString = inputString.split('\n');

    main();
});

function readLine() {
    return inputString[currentLine++];
}

/*
 * Complete the 'factorial' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts INTEGER n as parameter.
 */

function factorial(n) {
    // Write your code here
    if (n <= 1) {
        return 1
    }
    else{
        const result = n * factorial(n - 1)
        return result
    }
}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

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

    const result = factorial(n);

    ws.write(result + '\n');

    ws.end();
}