The Two Sneaky Numbers of Digitville

export function getSneakyNumbers(nums: number[]): number[] {
  const answer: number[] = [];
  const set = new Set<number>();
  for (const num of nums) {
    if (set.has(num)) {
      answer.push(num);
    } else {
      set.add(num);
    }
  }
  return answer;
}