Strange unique prime triplets: Difference between revisions
→{{header|Scala}}
Line 2,407:
=={{header|Scala}}==
<syntaxhighlight lang="scala">
val primeStream5 = LazyList.from(5, 6)
.flatMap(n => Seq(n, n + 2))
.filter(p => (5 to math.sqrt(p).floor.toInt by 6).forall(a => p % a > 0 && p % (a + 2) > 0))
val primes = LazyList(2, 3) ++ primeStream5
def isPrime(n: Int): Boolean =
if (n < 5) (n | 1) == 3
else primes.takeWhile(_ <= math.sqrt(n)).forall(n % _ > 0)
def triplets(limit: Int): Iterator[Seq[Int]] =
primes.takeWhile(_ <= limit)
.combinations{3}
.filter(primeTriplet => isPrime(primeTriplet.sum))
@main def main: Unit = {
for (list <- triplets(30)) {
val Seq(k, l, m) = list
println(f"$k%2d + $l%2d + $m%2d = ${list.sum}%2d")
}
for (limit <- Seq(30, 1000)) {
val start = System.currentTimeMillis
val num = triplets(limit).length
val duration = System.currentTimeMillis - start
println(f"number of prime triplets up to $limit%4d is $num%6d [time(ms): $duration%4d]")
}
}
</syntaxhighlight>
=={{header|Sidef}}==
<syntaxhighlight lang="ruby">for n in (30, 1000) {
| |||