dinic板子

 1 procedure dinic;
 2 begin
 3   while bfs do inc(ans,dfs(s,maxlongint));
 4 end;
 5 
 6 function bfs:boolean;
 7 var h,tail,i,j:longint;
 8 begin
 9   fillchar(dis,sizeof(dis),$3f);
10   h:=0;tail:=1;l[1]:=s;dis[s]:=0;
11   while h<>tail do
12   begin
13     inc(h);i:=l[h];j:=head[i];
14     while j>0 do
15     begin
16       if(dis[i]+1<dis[q[j]])and(flow[j]>0) then
17       begin
18         inc(tail);l[tail]:=q[j];
19         dis[q[j]]:=dis[i]+1;
20       end;
21       j:=next[j];
22     end;
23   end;
24   if dis[t]=$3f3f3f3f then exit(false) else exit(true);
25 end;
26 
27 function dfs(i,ll:longint):longint;
28 var j,tmp,x:longint;
29 begin
30   if i=t then exit(ll);
31   j:=head[i];x:=0;
32   while j>0 do
33   begin
34     if(flow[j]>0)and(dis[q[j]]=dis[i]+1) then
35     begin
36       tmp:=dfs(q[j],min(ll-x,flow[j]));
37       dec(flow[j],tmp);
38       inc(flow[j xor 1],tmp);
39       inc(x,tmp);
40       if x=ll then exit(ll);
41     end;
42     j:=next[j];
43   end;
44   if x=0 then dis[i]:=-1;
45   exit(x);
46 end;