public int sum13(int[] nums) {
  int sum = 0;
  for (int i = 0; i < nums.length; i++) {
    int n = nums[i];
    if (n == 13) {
      i++;
    }
    else {
      sum += n; // sum = sum + n;
    }
  }
  return sum;
}


public int sum13(int[] nums) {
  int sum = 0;
  boolean skipNext = false;
  for (int n : nums) {
    if (n == 13) {
      skipNext = true;
    }
    else if (skipNext) {
      skipNext = false;
    }
    else {
      sum += n; // sum = sum + n;
    }
  }
  return sum;
}