Cheryl's birthday: Difference between revisions
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<pre>[('July', '16')]</pre>
=={{header|Scala}}==
{{trans|D}}
<lang scala>import java.time.format.DateTimeFormatter
import java.time.{LocalDate, Month}
object Cheryl {
def main(args: Array[String]): Unit = {
val choices = List(
LocalDate.of(2019, Month.MAY, 15),
LocalDate.of(2019, Month.MAY, 16),
LocalDate.of(2019, Month.MAY, 19),
LocalDate.of(2019, Month.JUNE, 17),
LocalDate.of(2019, Month.JUNE, 18),
LocalDate.of(2019, Month.JULY, 14),
LocalDate.of(2019, Month.JULY, 16),
LocalDate.of(2019, Month.AUGUST, 14),
LocalDate.of(2019, Month.AUGUST, 15),
LocalDate.of(2019, Month.AUGUST, 17)
)
// The month cannot have a unique day because Albert knows the month, and knows that Bernard does not know the answer
val uniqueMonths = choices.groupBy(_.getDayOfMonth)
.filter(a => a._2.length == 1)
.flatMap(a => a._2)
.map(a => a.getMonth)
val filter1 = choices.filterNot(a => uniqueMonths.exists(b => a.getMonth == b))
// Bernard now knows the answer, so the day must be unique within the remaining choices
val uniqueDays = filter1.groupBy(_.getDayOfMonth)
.filter(a => a._2.length == 1)
.flatMap(a => a._2)
.map(a => a.getDayOfMonth)
val filter2 = filter1.filter(a => uniqueDays.exists(b => a.getDayOfMonth == b))
// Albert knows the answer too, so the month must be unique within the remaining choices
val birthDay = filter2.groupBy(_.getMonth)
.filter(a => a._2.length == 1)
.flatMap(a => a._2)
.head
// print the result
printf(birthDay.format(DateTimeFormatter.ofPattern("MMMM dd")))
}
}</lang>
{{out}}
<pre>July 16</pre>
=={{header|Sidef}}==
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