import util.

go =>
  Readings = [split(Record) : Record in read_file_lines("readings.txt")],
  DateStamps = new_map(),
  GoodReadings = 0,
  foreach({Rec,Id} in zip(Readings,1..Readings.length))
    if Rec.length != 49 then printf("Entry %d has bad_length %d\n", Id, Rec.length) end,
    Date = Rec[1],
    if DateStamps.has_key(Date) then
      printf("Entry %d (date %w) is a duplicate of entry %w\n", Id, Date, DateStamps.get(Date))
    else
      if sum([1: I in 3..2..49, check_field(Rec[I])]) == 0 then
         GoodReadings := GoodReadings + 1
      end
    end,
    DateStamps.put(Date, Id)
  end,
  nl,
  printf("Total readings: %d\n",Readings.len),
  printf("Good readings: %d\n",GoodReadings),
  nl.

check_field(Field) =>
  Field == "-2" ; Field == "-1" ; Field == "0".