MAX & MIN, Second Largest

let arr = [8, 3, 2, 5, 4, 7, 6, 1]

var maxValue = arr[0]
var minValue = arr[0]
var secondLargest: Int?

for value in arr[1...] {
  if value > maxValue {
    secondLargest = maxValue
    maxValue = value
  } else if value > secondLargest ?? 0 {
    secondLargest = value
  } else if value < minValue {
    minValue = value
  }
}

// Output: MaxValue 8
// Output: SecondLargest 7
// Output: MinValue 1