Java: большая постоянная хеш-структура?

Уточненный и исправленный ответ user2285781 для Swift 4:

    // reference: https://stackoverflow.com/a/15683034/347339
    func MKMapRectForCoordinateRegion(region:MKCoordinateRegion) -> MKMapRect {
        let topLeft = CLLocationCoordinate2D(latitude: region.center.latitude + (region.span.latitudeDelta/2), longitude: region.center.longitude - (region.span.longitudeDelta/2))
        let bottomRight = CLLocationCoordinate2D(latitude: region.center.latitude - (region.span.latitudeDelta/2), longitude: region.center.longitude + (region.span.longitudeDelta/2))

        let a = MKMapPointForCoordinate(topLeft)
        let b = MKMapPointForCoordinate(bottomRight)

        return MKMapRect(origin: MKMapPoint(x:min(a.x,b.x), y:min(a.y,b.y)), size: MKMapSize(width: abs(a.x-b.x), height: abs(a.y-b.y)))
    }

    // reference: https://stackoverflow.com/a/19307286/347339
    // assuming coordinates that create a polyline as well as a destination annotation
    func updateMap(coordinates: [CLLocationCoordinate2D], annotation: MKAnnotation) {

        var union = MKMapRectNull
        var coordinateArray = coordinates
        coordinateArray.append(annotation.coordinate)

        for coordinate in coordinateArray {
            // make a small, say, 50meter square for each
            let pReg = MKCoordinateRegionMakeWithDistance( coordinate, 50, 50 )
            // convert it to a MKMapRect
            let r = MKMapRectForCoordinateRegion(region: pReg)

            // union all of those
            union = MKMapRectUnion(union, r)
        }

        // expand the union, using the new #edgePadding call. T,L,B,R
        let f = mapView.mapRectThatFits(union, edgePadding: UIEdgeInsetsMake(70, 35, 10, 35))

        // NOTE you want the TOP padding much bigger than the BOTTOM padding
        // because the pins/signs are actually very tall

        mapView.setVisibleMapRect(f, animated: false)
    }