Jóladagatal 11/24 - Umturnun á stafrófi

factorial.js

// get factorial by iteration (faster than recursive)
Math.factorial = function (n) {
  var a = 1;
  for (var i = 2; i < n; i++) {
    a *= i;
  }
  return a;
}

// setup test case
var alphabet = 'AÁBDÐEÉFGHIÍJKLMNOÓPRSTUÚVXYÝÞÆÖ';
var target = 'JÓL';

// calculate answer
Math.factorial(alphabet.length - target.length + 1);