bzoj1391

最新推荐文章于 2018-04-26 20:52:18 发布

转载最新推荐文章于 2018-04-26 20:52:18 发布 · 61 阅读

0 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/phile/p/4473051.html

很像最大权闭合子图的题目
s向每个工作连边，流量为收益
每个工序，由工作i向对应机器连边，流量为租用费
每个机器向t连边，流量为购买费
显然跑最小割，ans=总收益-mincut

  1 const inf=200000007;
  2 type node=record
  3        flow,next,point:longint;
  4      end;
  5 
  6 var edge:array[0..3000010] of node;
  7     pre,p,cur,numh,h,d:array[0..3010] of longint;
  8     ans,n,m,j,t,len,a,b,x,y,i:longint;
  9 
 10 function min(a,b:longint):longint;
 11   begin
 12     if a>b then exit(b) else exit(a);
 13   end;
 14 
 15 procedure add(x,y,z:longint);
 16   begin
 17     inc(len);
 18     edge[len].point:=y;
 19     edge[len].flow:=z;
 20     edge[len].next:=p[x];
 21     p[x]:=len;
 22   end;
 23 
 24 function sap:longint;
 25   var tmp,u,i,j,q,neck:longint;
 26   begin
 27     for i:=0 to t do
 28       cur[i]:=p[i];
 29     numh[0]:=t+1;
 30     neck:=inf;
 31     u:=0;
 32     sap:=0;
 33     while h[0]<t+1 do
 34     begin
 35       d[u]:=neck;
 36       i:=cur[u];
 37       while i<>-1 do
 38       begin
 39         j:=edge[i].point;
 40         if (edge[i].flow>0) and (h[u]=h[j]+1) then
 41         begin
 42           pre[j]:=u;
 43           cur[u]:=i;
 44           neck:=min(neck,edge[i].flow);
 45           u:=j;
 46           if u=t then
 47           begin
 48             sap:=sap+neck;
 49             while u<>0 do
 50             begin
 51               u:=pre[u];
 52               j:=cur[u];
 53               dec(edge[j].flow,neck);
 54               inc(edge[j xor 1].flow,neck);
 55             end;
 56             neck:=inf;
 57           end;
 58           break;
 59         end;
 60         i:=edge[i].next;
 61       end;
 62       if i=-1 then
 63       begin
 64         dec(numh[h[u]]);
 65         if numh[h[u]]=0 then exit;
 66         q:=-1;
 67         tmp:=t;
 68         i:=p[u];
 69         while i<>-1 do
 70         begin
 71           j:=edge[i].point;
 72           if edge[i].flow>0 then
 73             if h[j]<tmp then
 74             begin
 75               q:=i;
 76               tmp:=h[j];
 77             end;
 78           i:=edge[i].next;
 79         end;
 80         h[u]:=tmp+1;
 81         inc(numh[h[u]]);
 82         cur[u]:=q;
 83         if u<>0 then
 84         begin
 85           u:=pre[u];
 86           neck:=d[u];
 87         end;
 88       end;
 89     end;
 90   end;
 91 
 92 begin
 93   len:=-1;
 94   fillchar(p,sizeof(p),255);
 95   readln(n,m);
 96   t:=n+m+1;
 97   for i:=1 to n do
 98   begin
 99     readln(a,b);
100     ans:=ans+a;
101     add(0,i,a);
102     add(i,0,0);
103     for j:=1 to b do
104     begin
105       readln(x,y);
106       add(i,n+x,y);
107       add(n+x,i,0);
108     end;
109   end;
110   for i:=1 to m do
111   begin
112     readln(x);
113     add(n+i,t,x);
114     add(t,n+1,0);
115   end;
116   writeln(ans-sap);
117 end.