public int[] post4(int[] nums) {
  int i = nums.length-1;
  while (i >= 0 && nums[i] != 4) {
    i--;
  }
  int count = i + 1;

  int len = nums.length - count;
  int[] a = new int[len];
  for (i = 0; i < len; i++) {
    a[i] = nums[count + i];
  }
  return a;
}