Give a map in input with the distance between two cities. Enter your current location and destination. This will return the shortest route between your current location and destination Now it will ask you whether you want to travel or not It will ask about your regular location and return the shortest route from your location to the destination And if you have lost your shortest route, that means if you will enter a place which is not present in your shortest path it will ask whether you want to change your destination or not and from your location to new destination will give the shortest path too.