PermMissingElem Scala 100%

gistfile1.scala

/*A zero-indexed array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
int solution(int A[], int N);
that, given a zero-indexed array A, returns the value of the missing element.
For example, given array A such that:
  A[0] = 2
  A[1] = 3
  A[2] = 1
  A[3] = 5
the function should return 4, as it is the missing element.
Assume that:
N is an integer within the range [0..100,000];
the elements of A are all distinct;
each element of array A is an integer within the range [1..(N + 1)].
Complexity:
expected worst-case time complexity is O(N);
expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).*/

object Solution extends App {
  def solution(A: Array[Int]): Int = {
    // write your code in Scala 2.10
    if (A.isEmpty) {
      1
    } else {
      val max = A.length + 1
      val set = A.toSet
      (1 to max).find(!set.contains(_)).get
    }
  }

  val res = solution(Array(2, 3, 1, 5))
  println(res)
}