let existing_path (stl,_ as auto) stn1 stn2 =
let st1 = ref (List.hd stl) in
let st2 = ref (List.hd stl) in
List.iter
(fun st ->
if st.nums=stn1 then st1:=st;
if st.nums=stn2 then st2:=st;
)
stl;
try
let _ = dijkstra (voisins auto) !st1 !st2 in
true
with
| Not_found -> false