Cheryl's birthday: Difference between revisions
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(cheryls-birthday *possible-dates*) ;; => ((16 . JULY)) |
(cheryls-birthday *possible-dates*) ;; => ((16 . JULY)) |
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</lang> |
</lang> |
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=={{header|D}}== |
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<lang d>import std.algorithm.iteration : filter, joiner, map; |
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import std.algorithm.searching : canFind; |
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import std.algorithm.sorting : sort; |
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import std.array : array; |
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import std.datetime.date : Date, Month; |
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import std.stdio : writeln; |
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void main() { |
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auto choices = [ |
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// Month.jan |
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Date(2019, Month.may, 15), |
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Date(2019, Month.may, 16), |
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Date(2019, Month.may, 19), // unique day (1) |
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Date(2019, Month.jun, 17), |
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Date(2019, Month.jun, 18), // unique day (1) |
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Date(2019, Month.jul, 14), |
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Date(2019, Month.jul, 16), // final answer |
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Date(2019, Month.aug, 14), |
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Date(2019, Month.aug, 15), |
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Date(2019, Month.aug, 17), |
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]; |
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// The month cannot have a unique day because Albert knows the month, and knows that Bernard does not know the answer |
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auto uniqueMonths = choices.sort!"a.day < b.day".groupBy.filter!"a.array.length == 1".joiner.map!"a.month"; |
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// writeln(uniqueMonths.save); |
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auto filter1 = choices.filter!(a => !canFind(uniqueMonths.save, a.month)).array; |
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// Bernard now knows the answer, so the day must be unique within the remaining choices |
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auto uniqueDays = filter1.sort!"a.day < b.day".groupBy.filter!"a.array.length == 1".joiner.map!"a.day"; |
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auto filter2 = filter1.filter!(a => canFind(uniqueDays.save, a.day)).array; |
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// Albert knows the answer too, so the month must be unique within the remaining choices |
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auto birthDay = filter2.sort!"a.month < b.month".groupBy.filter!"a.array.length == 1".joiner.front; |
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// print the result |
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writeln(birthDay.month, " ", birthDay.day); |
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}</lang> |
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{{out}} |
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<pre>jul 16</pre> |
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=={{header|F_Sharp|F#}}== |
=={{header|F_Sharp|F#}}== |