iOS - selecting second lowest number in integer array

Question

Let's say I have an array of numbers:

let numbers: [Int] = [1,2,3,4,5,6,7,8]

I want to pick out the second lowest number in that array but I don't want to use an index, I know you can pick the lowest and highest integer using min/maxElement dot notation so how would I get the second lowest or the second highest?

Answer 1

A direct implementation: (as Sulthan suggested?)

func secondMax(numbers: [Int]) -> Int {
    let (_, second) = numbers.reduce((Int.min, Int.min)) {(max2: (first: Int, second: Int), value: Int) in
        if value > max2.first {
            return (value, max2.first)
        } else if value > max2.second {
            return (max2.first, value)
        } else {
            return max2
        }
    }
    return second
}
print(secondMax([1,2,3,4,5,6,7,8])) //->7
print(secondMax([1,1,2,3,4,4])) //->4
print(secondMax([5,5,6,1,2,3,4])) //->5
print(secondMax([5,6,6,1,2,3,4])) //->6