Schedule generateRandomSchedule(int x, int y, int i, int j){
        Schedule s = new Schedule(new RoomScheme[x][y]);
        for(int k=0; k<x; k++){
            for(int m=0; m<y; m++){
                s.schedule[k][m] = generateRandomScheme(i, j, d.subject);
            }
        } return s;
    }