code: function getRandomArray (n) {
    var res, next;
  
    if (n === 0) { return []; }
    if (n === 1) { return [0]; }
  
    res = getRandomArray(n - 1);
    next = Math.floor(Math.random() * n);
    res.splice(next, 0, n - 1);   // Add n-1 at a random position in the array
  
    return res;
  }
docs: Return an array with the numbers from 0 to n-1, in a random order