var head:Int = 0
var num:Int = 0
var max:Int = 0
var data:[Any]!
var debug = false

init(_ max:Int) {
    self.max = max
    self.data = Array<Any>(repeating: -1, count: max)
}

@discardableResult
func enqueue(_ obj:Any) -> Bool { // キューが一杯だったらfalseを返す
    if num < max {
        self.data[(head + num) % max] = obj
        num = num + 1
        return true
    }
    return false
}

@discardableResult
func dequeue() -> Any? {
    if num > 0 {
        let obj = data[head]
        data[head] = -1
        num = num - 1
        head = (head + 1) % max;
        return obj
    }
    return nil
}