POJ1273 dinic Pascal模板

之前写的其实不是dinic真不好意思……耽误大家了。现在重写了一个真正的dinic。 2013-05-13

program dinic;

//Algorithm:Dinic for Network
//Author:HT
//Date:2013/05/10

Const
 inf=1000000;

Type
 rec=record
   s,e,w,flow,next:longint;
 end;

Var
 b,d,q:array[0..300] of longint;
 a:array[-1..450] of rec;
 v:array[0..300] of boolean;
 n,m,i,st,ed,ww,top,tar:longint;

Function min(a,b:longint):longint;inline;begin if a<b then exit(a);exit(b); end;

Procedure Add(st,ed,ww:longint);inline;
  begin
  inc(top);
  with a[top] do begin s:=st; e:=ed;w:=ww;next:=b[st]; end;
  b[st]:=top;
end;

function bfs:boolean;
var
 head,tail,x,u:longint;
 y:rec;
  begin
  fillchar(v,sizeof(v),false);
  tail:=1;head:=0;d[st]:=1;
  v[st]:=true;
  q[1]:=st;
  while head<tail do
    begin
    inc(head);
    x:=q[head];
    u:=b[x];
    while u<>b[0] do
      begin
      y:=a[u];
      if (not v[y.e]) and (y.flow<y.w) then
        begin
        v[y.e]:=true;
        d[y.e]:=d[x]+1;
        inc(tail);
        q[tail]:=y.e;
      end;
      u:=y.next;
    end;
  end;
  exit(v[tar]);
end;

Function Addflow(p,maxflow:longint):longint;
var
 u,o:longint;
 y:rec;
  begin
  if (p=tar) or (maxflow=0) then exit(maxflow);
  addflow:=0;
  u:=b[p];
  while u<>b[0] do
    begin
    y:=a[u];
    if (d[y.e]=d[p]+1) and (y.flow<y.w) then
      begin
      o:=Addflow(y.e,min(maxflow,y.w-y.flow));
      if o>0 then
        begin
        inc(a[u].flow,o);
        dec(a[u xor 1].flow,o);
        dec(maxflow,o);
        inc(addflow,o);
        if maxflow=0 then break;
      end;
    end;
    u:=y.next;
  end;

end;


function network:longint;
  begin
  network:=0;
  while bfs do
    begin
    inc(network,addflow(st,inf));
    //writeln('network=',network);
  end;
end;

  begin

  while not eof do begin
  fillchar(b,sizeof(b),$ff);
  fillchar(a,20*(2*m+2),0);
  readln(m,n); top:=-1;
  for i:=1 to m do
    begin
    readln(st,ed,ww);
    Add(st,ed,ww);
    Add(ed,st,0);
  end;
  st:=1;tar:=n;
  writeln(Network);   end;

end.