           Home  z-mall  st.pet  office  school   motel  restr. library airport  barber
    Home       0       9       0       7       8       7       9       1       0       6
  z-mall       9       0       8       9       0       7       6       5       2       2
  st.pet       0       8       0       6       7       1       4       2       3       1
  office       7       9       6       0       0       1       7       3       5       2
  school       8       0       7       0       0       6       0       0       1       5
   motel       7       7       1       1       6       0       2       8       8       6
  restr.       9       6       4       7       0       2       0       1       6       3
 library       1       5       2       3       0       8       1       0       6       5
 airport       0       2       3       5       1       8       6       6       0       9
  barber       6       2       1       2       5       6       3       5       9       0


minimum spanning tree:
    z-mall <-2->   barber
    st.pet <-2->  library
    office <-1->    motel
    school <-1->  airport
     motel <-1->   st.pet
    restr. <-1->  library
   library <-1->     Home
   airport <-2->   z-mall
    barber <-1->   st.pet
total cost = 12
