ProjectEuler in Scala

Problem 1 - Multiples of 3 and 5.scala

1 to 1000 - 1 filter(x => x % 3 == 0 || x % 5 == 0) sum

Problem 2 - Even Fibonacci numbers.scala

val fibonacci: Stream[Int] = 1 #:: fibonacci.scanLeft(2)(_+_)

fibonacci filter (_ % 2 == 0) takeWhile(_ < 4000000) sum

Problem 21 - Amicable numbers.sc

val numbers = 1 to 10000

val properDivisorsSum = numbers.map(e => (e, numbers slice(0, e/2) filter(e % _ == 0) sum))

properDivisorsSum
.filter{case(a,b) => properDivisorsSum exists{case(c,d) => a != b && a == d && b == c}}
.map(_._1)
.sum

Problem 48 - Self powers.sc

(1 to 1000).map(x => BigInt(x).pow(x)).sum % BigInt(10).pow(10)

Problem 6 - Sum square difference.sc

val range = 1 to 100

Math.pow(range.sum, 2).toInt - range.map(x => x * x).sum