bzoj3876

不高兴的回忆啊啊啊
当初这种简单题因为自己作死就暴零0了
这题在OJ上是简单的最小有下界费用流，增广到正费用为止
因为算的是总时限
但实际的话似乎要用pacman吃豆豆那题的方法先用dp跑出第一次的增广路再用spfa增广

 const inf=;
 type node=record
        cost,flow,next,point:longint;
      end;

 var edge:array[..] of node;
     p,pre,cur,d:array[..] of longint;
     q:array[..] of longint;
     v:array[..] of boolean;
     j,i,n,m,s,t,len,x,y:longint;

 procedure add(x,y,f,w:longint);
   begin
     inc(len);
     edge[len].point:=y;
     edge[len].flow:=f;
     edge[len].cost:=w;
     edge[len].next:=p[x];
     p[x]:=len;
   end;

 function spfa:boolean;
   var i,j,x,y,f,r:longint;
   begin
     f:=;
     r:=;
     d[]:=;
     for i:= to t do
       d[i]:=;
     fillchar(v,sizeof(v),false);
     q[]:=;
     v[]:=true;
     while f<=r do
     begin
       x:=q[f];
       v[x]:=false;
       i:=p[x];
       while i<>- do
       begin
         y:=edge[i].point;
         if edge[i].flow> then
           if d[y]>edge[i].cost+d[x] then
           begin
             d[y]:=edge[i].cost+d[x];
             pre[y]:=x;
             cur[y]:=i;
             if not v[y] then
             begin
               inc(r);
               q[r]:=y;
               v[y]:=true;
             end;
           end;
         i:=edge[i].next;
       end;
       inc(f);
     end;
     if d[t]= then exit(false) else exit(true);
   end;

 function mincost:longint;
   var i,j,s:longint;
   begin
     mincost:=;
     s:=;
     while spfa do
     begin
       if d[t]>= then exit;
       i:=t;
       while i<> do
       begin
         j:=cur[i];
         dec(edge[j].flow);
         inc(edge[j xor ].flow);
         i:=pre[i];
       end;
       mincost:=mincost+d[t];
     end;
   end;

 begin
   readln(n);
   fillchar(p,sizeof(p),);
   len:=-;
   t:=n+;
   for i:= to n do
   begin
     read(s);
     m:=m+s;
     for j:= to s do
     begin
       read(x,y);
       add(i,x,,-inf+y);
       add(x,i,,inf-y);
       add(i,x,inf,y);
       add(x,i,,-y);
     end;
     add(i,t,inf,);
     add(t,i,,);
   end;
   writeln(mincost+m*inf);
 end.