Schedule task - keep order

func getSchedule(_ arr: [Int], _ space: Int) -> [Int]{
    guard space > 0 else {
        return arr
    }
    var res = [Int]()
    var p = 0
    var map = [Int: Int]()  // integer, last index


    while p < arr.count{
        let number = arr[p]
        if let last = map[number]{
            var diff = space - (res.count - last)
            while diff > 0{
                res.append(-1)
                diff -= 1
            }
        }
        res.append(arr[p])
        map[number] = res.count
        p += 1
    }
    return res
}


let arr = [1,1,2,3,2,1]
print(getSchedule(arr, 2))

//[1, -1, -1, 1, 2, 3, -1, 2, 1]


func getSchedule2(_ arr: [Int], _ space: Int) -> Int{
    guard space > 0 else {
        return arr.count
    }
    var count = 0
    var p = 0
    var map = [Int: Int]()  // integer, last index

    while p < arr.count{
        let number = arr[p]
        if let last = map[number]{
            if (count - last) < space {
                count = last + space
            }
        }
        count += 1
        map[number] = count
        p += 1
    }
    return count
}


let arr2 = [1,1,2,3,2,1]
print(getSchedule2(arr2, 2))