FindTheOddInt

My:
object FindTheOddInt {
  def findOdd(xs: Seq[Int], index:Int=0): Int = {
    if(xs.count(x=>x==xs(index))%2==0) findOdd(xs, index+1)
    else xs(index)
  }
}

Other:
object FindTheOddInt {
  def findOdd(xs: Seq[Int]): Int = xs.reduce(_ ^ _)
}