竞赛图一般是把每场比赛当作一个点,然后和相应球队连边
每场比赛一赢一输对两支球队都有影响看起来不好搞
实际上我们可以先假设参加后面后面所有球队都输(每场比赛双输)
然后对每场比赛我们选择一支球队赢计算增加的收益,这样就很简单了
下面就是经典的平方流的做法

  1 const inf=2147483647;
  2 type node=record
  3        flow,next,cost,po:longint;
  4      end;
  5 
  6 var e:array[0..400010] of node;
  7     q:array[0..1000010] of longint;
  8     s,a,b,l,w,p,cur,pre,d:array[0..6010] of longint;
  9     v:array[0..6010] of boolean;
 10     ans,len,i,j,x,y,n,m,t:longint;
 11 
 12 procedure add(x,y,f,c:longint);
 13   begin
 14     inc(len);
 15     e[len].po:=y;
 16     e[len].flow:=f;
 17     e[len].cost:=c;
 18     e[len].next:=p[x];
 19     p[x]:=len;
 20   end;
 21 
 22 procedure build(x,y,f,c:longint);
 23   begin
 24     add(x,y,f,c);
 25     add(y,x,0,-c);
 26   end;
 27 
 28 function spfa:boolean;
 29   var x,y,i,f,r:longint;
 30   begin
 31     f:=1;
 32     r:=1;
 33     q[1]:=0;
 34     fillchar(v,sizeof(v),false);
 35     for i:=1 to t do
 36       d[i]:=inf;
 37     d[0]:=0;
 38     while f<=r do
 39     begin
 40       x:=q[f];
 41       v[x]:=false;
 42       i:=p[x];
 43       while i<>-1 do
 44       begin
 45         y:=e[i].po;
 46         if e[i].flow>0 then
 47           if d[y]>d[x]+e[i].cost then
 48           begin
 49             cur[y]:=i;
 50             pre[y]:=x;
 51             d[y]:=d[x]+e[i].cost;
 52             if not v[y] then
 53             begin
 54               inc(r);
 55               q[r]:=y;
 56               v[y]:=true;
 57             end;
 58           end;
 59         i:=e[i].next;
 60       end;
 61       inc(f);
 62     end;
 63     if d[t]=inf then exit(false) else exit(true);
 64   end;
 65 
 66 function mincost:longint;
 67   var i,j:longint;
 68   begin
 69     mincost:=0;
 70     while spfa do
 71     begin
 72       mincost:=mincost+d[t];
 73       i:=t;
 74       while i<>0 do
 75       begin
 76         j:=cur[i];
 77         dec(e[j].flow);
 78         inc(e[j xor 1].flow);
 79         i:=pre[i];
 80       end;
 81     end;
 82   end;
 83 
 84 begin
 85   len:=-1;
 86   fillchar(p,sizeof(p),255);
 87   readln(n,m);
 88   for i:=1 to n do
 89     readln(w[i],l[i],a[i],b[i]);
 90   t:=n+m+1;
 91   for i:=1 to m do
 92   begin
 93     readln(x,y);
 94     inc(s[x]);
 95     inc(s[y]);
 96     build(0,i,1,0);
 97     build(i,x+m,1,0);
 98     build(i,y+m,1,0);
 99   end;
100   for i:=1 to n do
101   begin
102     ans:=ans+a[i]*sqr(w[i])+b[i]*sqr(s[i]+l[i]);
103     for j:=1 to s[i] do
104       build(i+m,t,1,(a[i]+b[i])*(2*j-1)+2*w[i]*a[i]-2*b[i]*(s[i]+l[i]));
105   end;
106   writeln(mincost+ans);
107 end.
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posted on 2015-02-07 10:52  acphile  阅读(128)  评论(0编辑  收藏  举报