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/* The Computer Language Shootout
http://shootout.alioth.debian.org/
contributed by Isaac Gouy
*/
import scala.collection.mutable.BitSet
object nsievebits {
def nsieve(m: Int) = {
val isPrime = new BitSet(m+1)
isPrime ++= Iterator.range(2, m+1)
for (i <- Iterator.range(2, m+1)) {
if (isPrime.contains(i)) {
var k = i+i
while (k <= m){ isPrime -= k; k = k+i }
}
}
isPrime.size
}
def main(args: Array[String]) {
def printPrimes(m: Int) = {
def pad(i: Int, width: Int) = {
val s = i.toString
List.range(0, width - s.length)
.map((i) => " ") .foldLeft("")((a,b) => a+b) + s
}
Console.println("Primes up to " + pad(m,8) + pad(nsieve(m),9))
}
val n = Integer.parseInt(args(0))
printPrimes( (1<<n )*10000 )
printPrimes( (1<<n-1)*10000 )
printPrimes( (1<<n-2)*10000 )
}
}
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