【BZOJ4398】福慧双修（二进制，最短路）

题意：

此题中S=1

思路：Orz ManGod秒切此题

我觉得出入边权互换不太直观，就改了一下写法

第一次默认与1有关的第一条出边只出不入，第二次默认只入不出

 var q,dis:array[..]of longint;
     head,vet,next,len,flag,x,y,z,w,id,a,b,c,d:array[..]of longint;
     inq:array[..]of boolean;
     n,m,bz,t3,t4,tot,h1,t1,i,j,ans,m1,t,tmp:longint;

 procedure add(a,b,c:longint);
 begin
  inc(tot);
  next[tot]:=head[a];
  vet[tot]:=b;
  len[tot]:=c;
  head[a]:=tot;
 end;

 function who(x,y:longint):longint;
 begin
  if x= then exit(y);
  exit(x);
 end;

 function min(x,y:longint):longint;
 begin
  if x<y then exit(x);
  exit(y);
 end;

 procedure spfa;
 var u,e,v,t,w:longint;
 begin
  t:=; w:=t1;
  while h1<t1 do
  begin
   inc(h1); inc(t);
   if t=*n+ then t:=;
   u:=q[t]; inq[u]:=false;
   e:=head[u];
   while e<> do
   begin
    v:=vet[e];
    if (flag[e]=)and(dis[u]+len[e]<dis[v]) then
    begin
     dis[v]:=dis[u]+len[e];
     if not inq[v] then
     begin
      inc(t1); inc(w);
      if w=*n+ then w:=;
      q[w]:=v; inq[v]:=true;
     end;
    end;
    e:=next[e];
   end;
  end;
 end;

 procedure swap(var x,y:longint);
 var t:longint;
 begin
  t:=x; x:=y; y:=t;
 end;

 begin
  assign(input,'bzoj4398.in'); reset(input);
  assign(output,'bzoj4398.out'); rewrite(output);
  readln(n,m1);
  for i:= to m1 do
  begin
   read(x[i],y[i],z[i],w[i]);
   if (x[i]=)or(y[i]=) then
   begin
    inc(m); id[m]:=i;
    a[m]:=x[i]; b[m]:=y[i]; c[m]:=z[i]; d[m]:=w[i];
   end;
   add(x[i],y[i],z[i]);
   add(y[i],x[i],w[i]);
  end;

  t:=trunc(ln(n)/ln())+;
  ans:=maxlongint;
  for i:= to t do
  begin
   for j:= to tot do flag[j]:=;
   bz:=who(a[],b[]);
   if a[]= then flag[id[]<<]:=
    else flag[(id[]<<)-]:=; //out

   fillchar(inq,sizeof(inq),false);
   fillchar(dis,sizeof(dis),$7f);
   h1:=; t1:=;
   inc(t1); q[t1]:=bz; inq[bz]:=true;
   if a[]= then dis[bz]:=c[]
    else dis[bz]:=d[];

   for j:= to m do
   begin
    tmp:=who(a[j],b[j]);
    t3:=bz and (<<(i-));
    t4:=tmp and (<<(i-));
    if t3<>t4 then    //in
    begin
     if a[j]= then flag[(id[j]<<)-]:=
      else flag[id[j]<<]:=;
    end
     else    //out
     begin
      if a[j]= then flag[id[j]<<]:=
       else flag[(id[j]<<)-]:=;
      inc(t1); q[t1]:=tmp; inq[tmp]:=true;
      if a[j]= then dis[tmp]:=c[j]
       else dis[tmp]:=d[j];
     end;
   end;
   spfa;
   ans:=min(ans,dis[]);
  end;

  for i:= to t do
  begin
   for j:= to tot do flag[j]:=;
   bz:=who(a[],b[]);
   if a[]= then flag[(id[]<<)-]:=
    else flag[id[]<<]:=; //in

   fillchar(inq,sizeof(inq),false);
   fillchar(dis,sizeof(dis),$7f);
   h1:=; t1:=;

   for j:= to m do
   begin
    tmp:=who(a[j],b[j]);
    t3:=bz and (<<(i-));
    t4:=tmp and (<<(i-));
    if t3<>t4 then    //out
    begin
     if a[j]= then flag[id[j]<<]:=
      else flag[(id[j]<<)-]:=;
     inc(t1); q[t1]:=tmp; inq[tmp]:=true;
     if a[j]= then dis[tmp]:=c[j]
      else dis[tmp]:=d[j];
    end
     else    //in
     begin
      if a[j]= then flag[(id[j]<<)-]:=
       else flag[id[j]<<]:=;
     end;
   end;
   spfa;
   ans:=min(ans,dis[]);
  end;
  if ans> then writeln(-)
   else writeln(ans);
  close(input);
  close(output);
 end.