**Paste:**#107328**Author:**1HaskellADay**Language:**Haskell**Channel:**-**Created:**2014-07-11 10:03:55 UTC**Revisions:**- 2014-07-12 04:07:30 UTC #107375 (diff): No title (1HaskellADay)
- 2014-07-11 10:07:55 UTC #107330 (diff): No title (1HaskellADay)
- 2014-07-11 10:04:53 UTC #107329 (diff): No title (1HaskellADay)
- 2014-07-11 10:03:55 UTC #107328: It's Friday, Friday! Gotta get down on Friday! (1HaskellADay)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | import Locale -- or: import System.Locale import Data.Time.LocalTime import Data.Time.Calendar import Data.Time.Format import Data.Time.Calendar.MonthDay import Data.Set (Set) import qualified Data.Set as Set {-- The description of the problem is ripped nearly verbatim from http://www.cadaeic.net/calendar.htm " New York Minutes Suppose an hour, minute, day, month, and year are written down on five pieces of paper and mixed. Define a New York Minute as an instant in time for which it is possible to reconstruct, by logical argument, the original order of the five fields. (This nomenclature is a reference to the song "New York Minute" by Don Henley, in which "everything can change". In a New York Minute, everything can change and yet it is still possible to reconstruct the original order.) Do New York Minutes exist? The answer is "yes": for example, 9:47 on 12/31/90. The 90 must be the year, as it is too large for any other field, and similarly 47 must be the minute and 31 must be the day. The remaining two (9 and 12) are uniquely determined because September has only 30 days, so 9/31 would be illegal. Now for the puzzle: How many minutes elapse between the last New York Minute in 1999 and the first New York Minute in 2000? Since the calendar repeats exactly every 400 years (proof: there are 97 leap days every 400 years, and 365*400+97 is a multiple of 7), it is possible to calculate exactly how many New York Minutes there are. This number is 3,782,800 out of the 210,379,680 minutes in 400 years. In other words, about 1.8% of all minutes. But note that these are very irregularly spaced relative to the years. The years 1998 and 1999 each have 23,256 New York Minutes, but the year 2000 only has 622! (In fact, not until the year 2060 are New York Minutes as plentiful as they are in 1999.) " Mike Kieth 1. For a given time, t, determine whether this time is a New York Minute: --} isNYminute :: LocalTime -> Bool isNYminute time = undefined {-- 2. From a set of input numbers, construct a New York Minute, if possible: --} mkNYminute :: Set Int -> Maybe LocalTime mkNYminute numbers = undefined {-- 3. Does today have any New York Minutes? If so, what are they, specifically? --} todaysNYminutes :: IO [LocalTime] -- Today comes from the ... RealWorld .. EEK! todaysNYminutes = undefined {-- 4. More generally, for any given day, d, what, if any, are the New York Minutes? --} daysNYminutes :: Day -> [LocalTime] daysNYminutes day = undefined {-- 'Now, for something completely different' than 'In a New York Minute' ... Explanatory note on the title of this exercise: "It's Friday, Friday! Gotta get down on Friday!" are the opening lyrics to Rebecca Black's famous (infamous?) song popularized on youtube.com. --} -- a rather ... 'comprehensive' solution is provided at http://lpaste.net/107370 |