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=420007;
type node=record
       cost,flow,next,point:longint;
     end;

var edge:array[0..200010] of node;
    p,pre,cur,d:array[0..310] of longint;
    q:array[0..1000010] of longint;
    v:array[0..310] 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:=1;
    r:=1;
    d[1]:=0;
    for i:=2 to t do
      d[i]:=100000007;
    fillchar(v,sizeof(v),false);
    q[1]:=1;
    v[1]:=true;
    while f<=r do
    begin
      x:=q[f];
      v[x]:=false;
      i:=p[x];
      while i<>-1 do
      begin
        y:=edge[i].point;
        if edge[i].flow>0 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]=100000007 then exit(false) else exit(true);
  end;

function mincost:longint;
  var i,j,s:longint;
  begin
    mincost:=0;
    s:=0;
    while spfa do
    begin
      if d[t]>=0 then exit;
      i:=t;
      while i<>1 do
      begin
        j:=cur[i];
        dec(edge[j].flow);
        inc(edge[j xor 1].flow);
        i:=pre[i];
      end;
      mincost:=mincost+d[t];
    end;
  end;

begin
  readln(n);
  fillchar(p,sizeof(p),255);
  len:=-1;
  t:=n+1;
  for i:=1 to n do
  begin
    read(s);
    m:=m+s;
    for j:=1 to s do
    begin
      read(x,y);
      add(i,x,1,-inf+y);
      add(x,i,0,inf-y);
      add(i,x,inf,y);
      add(x,i,0,-y);
    end;
    add(i,t,inf,0);
    add(t,i,0,0);
  end;
  writeln(mincost+m*inf);
end.