10/01/2010 02:50:00
Scala | Project Euler Probrem 2
import scala.collection.mutable
def isEven(n: BigInt): Boolean = (n % 2 == 0)
var fibs = mutable.Map[Int, BigInt]()
def fib(n: Int): BigInt = {
if (fibs.isDefinedAt(n)) return fibs(n)
if (n <= 2) return 1;
fibs(n) = fib(n - 1) + fib(n - 2)
return fibs(n)
}
var result = (1 to 28).map(n => fib(n)).reduceLeft { (a, b) => if (isEven(b)) println(a, b); if (isEven(b)) a + b else a + 0 }
println(result)
//(1,2)
//(3,8)
//(11,34)
//(45,144)
//(189,610)
//(799,2584)
//(3383,10946)
//(14329,46368)
//(60697,196418)
//257115--------------------------------------------------------------------------------
