Brazilian numbers: Difference between revisions
→fuctional
Line 4,066:
7 13 31 43 73 127 157 211 241 307 421 463 601 757 1093 1123 1483 1723 2551 2801 </pre>
===fuctional===
<lang Scala>
object Brazilian extends App {
def oddPrimes =
LazyList.from(3, 2).filter(p => (3 to math.sqrt(p).ceil.toInt by 2).forall(p % _ > 0))
val primes = 2 #:: oddPrimes
def sameDigits(num: Int, base: Int): Boolean = {
val first = num % base
@annotation.tailrec
def iter(num: Int): Boolean = {
if (num % base) == first then iter(num / base)
else num == 0
}
iter(num / base)
}
def isBrazilian(num: Int): Boolean = {
num match {
case x if x < 7 => false
case x if (x & 1) == 0 => true
case _ => (2 to num - 2).exists(sameDigits(num,_))
}
}
val (limit, bigLimit) = (20, 100_000)
val doList = Seq(("brazilian", LazyList.from(7)),
("odd", LazyList.from(7, 2)),
("prime", primes))
for((listStr, stream) <- doList)
println(s"$listStr: " + stream.filter(isBrazilian(_)).take(limit).toList)
println("be a little patient, it will take some time")
val bigElement = LazyList.from(7).filter(isBrazilian(_)).drop(bigLimit - 1).take(1).head
println(s"brazilian($bigLimit): $bigElement")
}
</lang>
=={{header|Sidef}}==
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