Codility - PermCheck (https://codility.com/demo/results/demoC7B3DN-3UN/)

CodilityPermCheck.scala

import java.util.BitSet

object Solution {
    def solution(A: Array[Int]): Int = {
        val bitz = new BitSet(A.size + 1)
        
        val good = A.foldLeft(true)((current, i) => 
            if (current) {
                (i, bitz.get(i)) match {
                    case (x, _) if x > A.size => 
                        false
                        
                    case (x, _) if x < 1 || x > 1000000000 => 
                        false
                        
                    case (0, _) => 
                        false
                        
                    case (_, true) => 
                        false
                        
                    case _ =>
                        bitz.set(i)
                        true
                }
                
            } else false
        )
        
        if (good && A.size > 0 && A.size <= 100000) 1
        else 0
    }
}