@Override
    public void addClient(Client client) {
        int waitingTime = 0;
        for(Client c : clients){
            waitingTime += c.getServiceTime();
        }
        client.setWaitingTime(waitingTime);
        clients.add(client);
        
        totalServiceTime += client.getServiceTime();
        totalWaitingTime += waitingTime;
        totalClientNumber ++;
    }