Code optimization on minutes pr hour calculation

Question

The following code takes a timeframe in minutes since midnight and creates an array with minutes pr hour. But, it's slow. Any better suggestions out there? (no, changing language is not an option :-) )

Const clDeparture   As Long = 123
Const clArrival     As Long = 233
Dim lHour           As Long
Dim lMinute         As Long
Dim alHour(25)      As Long

For lMinute = 0 To 1440
    If lMinute >= clDeparture And lMinute < clArrival Then
        alHour(Int(lMinute / 60)) = alHour(Int(lMinute / 60)) + 1
    End If
Next

The array should now contain:

(0,0) (1,0) (2,57) (3,53) (4,0) .....

Regards

Answer 1

You want to know how many minutes of each hour are in the time span?
I think this should do it, or something close to it:

lDepHour = Int(clDeparture / 60)
lDepMinute = clDeparture - lDepHour * 60
lArrHour = Int(clArrival / 60)
lArrMinute = clArrival - lArrHour * 60

If (lDepHour = lArrHour) Then
  alHour(lDepHour) = lArrMinute - lDepMinute
Else
  alHour(lDepHour) = 60 - lDepMinute
  alHour(lArrHour) = lArrMinute
  For lHour = lDepHour + 1 To lArrHour - 1
    alHour(lHour) = 60
  End For
End If

This should be about 60 times faster than what you've got.

P.S. If the time span can span midnight (arrival < departure) then add 24*60 to the arrival time, do the same logic, and if lHour >= 24, put the numbers in lHour - 24.