pascal六城市问题源代码

program tu3bfs;
type fg=set of 1..6;
const link:array[1..5,1..6] of integer=((0,4,8,0,0,0),
(4,0,3,4,6,0),(8,3,0,2,2,0),(0,4,2,0,4,9),(0,6,2,4,0,4));
var pnt,city:array[1..10] of 0..6;
flag:fg;
r,k,head,tail:integer;
procedure print;
var n, i,cost,y:integer;
s:array[1..7] of 1..6;
begin
y:=tail;n:=0; cost:=0;
while y>0 do begin inc(n);s[n]:=y;y:=pnt[y] end;
writeln('minpath=',n-1);
write('1');
for i:=n-1 downto 1 do
begin
write('->',s[i]);
cost:=cost+link[s[i+1],s[i]];
end;
writeln;
writeln('cost=',cost);
end;
begin
flag:=[1];
pnt[1]:=0; city[1]:=1;
head:=0;tail:=1;
repeat
head:=head+1;
k:=city[head];
for r:=2 to 6 do
if not(r in flag) and (link[k,r]>0) then
begin
inc(tail);city[tail]:=r;
pnt[