SWM

gistfile1.txt

const isPrime = (num) => {
  for (let i = 2, s = Math.sqrt(num); i <= s; i++)
    if (num % i === 0) return false;
  return num > 1;
};

const func = (A, B) => {
  const obj = {};

  B.forEach((e) => {
    if (!obj.hasOwnProperty(e)) {
      obj[e] = 1;
    } else {
      obj[e]++;
    }
  });

  // check if prime once, instead A.length times
  for (const key in obj) {
    if (isPrime(obj[key])) {
      obj[key] = -1;
    }
  }

  return A.filter((e) => {
    return obj[e] !== -1;
  });
};