minimumMaximum.swift

func minimumMaximum<T: Comparable>(_ array: [T]) -> (minimum: T, maximum: T)? {
  var array = array
  guard !array.isEmpty else {
    return nil
  }

  var minimum = array.first!
  var maximum = array.first!

  let hasOddNumberOfItems = array.count % 2 != 0
  if hasOddNumberOfItems {
    array.removeFirst()
  }

  while !array.isEmpty {
    let pair = (array.removeFirst(), array.removeFirst())
    if pair.0 > pair.1 { //if the first number if greater than the second number 
      if pair.0 > maximum { 
        maximum = pair.0
      }
      if pair.1 < minimum {
        minimum = pair.1
      }
    } else {
      if pair.1 > maximum {
        maximum = pair.1
      }
      if pair.0 < minimum {
        minimum = pair.0
      }
    }
  }

  return (minimum, maximum)
}
let array = [ 8, 3, 9, 4, 6 ]
let result = minimumMaximum(array)!
print(result.minimum)   // This will return 3
print(result.maximum)   // This will return 9