How to check if a time (minute/second) is in a given interval?

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+1 Q:

How to check if a time (minute/second) is in a given interval?

So I have a physical chart of time intervals (minute:second) which map to point values (for example: 9:59-10:10 = 59.7) and I need to write a program that tries to find out the point value for a given time (such as 10:02 would return 59.7).

I would also like to have the interval chart stored in a .properties file, so my other "calculators" are all consistent.

What would be the best way to program this?

+4 A:

One simple way would be to map the time to an integer - either number of seconds through the day (minutes * 60 + seconds) or just effectively "remove the colon" mapping 9:59 to 959, and 10:10 to 1010 (minutes * 100 + seconds).

Then each interval is just a pair of integers. If you have lots of intervals you may want to store them in a sorted list and perform a binary chop - if you don't have very many of them (or don't need to do this very often) then simply having a list of interval/value and walking through the list would be pretty simple.

Jon Skeet 2010-09-05 14:30:30

I see what you're saying, but should I have the time mappings set to the start of each interval? For example, one interval is 9:59-10:10 with a value of 59.7. So should I store 959=59.7 and then 1011=57.5? Since 1011 would be the start of the new interval?

Fran Fitzpatrick 2010-09-07 15:15:41

That depends... do intervals ever overlap? It might be simplest to store the raw data (i.e. both ends of the interval and the value associated with the interval) rather than try to do away with half of it. But without knowing more about the context, it's hard to say for sure.

Jon Skeet 2010-09-07 16:05:43

Correct, the intervals will never overlap.

Fran Fitzpatrick 2010-09-07 17:06:05

@Fran: And will there ever be any gaps, or will the end of one always be exactly the start of the next?

Jon Skeet 2010-09-07 17:33:34

There will never be any gaps. The start of one interval will always be one second more than the end of the previous interval.

Fran Fitzpatrick 2010-09-07 17:36:55

@Fran: In that case you can indeed regard it just as a sequence of start times. Have a list of start/value pairs, sorted by start time, and then just do a binary chop with the requested time to find the appropriate value.

Jon Skeet 2010-09-07 17:49:48

Thanks, Jon! :-D

Fran Fitzpatrick 2010-09-07 17:57:40

ansaurus

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How to check if a time (minute/second) is in a given interval?

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