二分图最佳匹配（网络流）

来源：互联网发布：数据库2000支持w7吗编辑：程序博客网时间：2024/05/19 17:51

var t,ii,i,j,n,cost,top,tail,min,tt,ttf:longint;    pre,d:array[1..1000]of longint;    b:array[1..10000]of longint;    flag:array[1..1000]of boolean;    f,c:array[1..200,1..200]of longint;begin read(t); for ii:=1 to t do  begin   fillchar(f,sizeof(f),0);   fillchar(c,sizeof(c),0);   read(n);   for i:=2 to n+1 do    for j:=n+2 to n+n+1 do     begin      read(c[i,j]);      c[j,i]:=-c[i,j];      f[i,j]:=1;      f[j,i]:=0;     end;   for i:=1 to n do    for j:=1 to n do     read(tt);   for i:=2 to n+1 do    begin     c[1,i]:=0;     c[i,1]:=0;     f[1,i]:=1;     f[i,1]:=0;    end;   for i:=n+2 to 2*n+1 do    begin     c[i,2*n+2]:=0;     c[2*n+2,i]:=0;     f[i,2*n+2]:=1;     f[2*n+2,i]:=0;    end;   ttf:=0;   cost:=0;   while true do begin   top:=1;tail:=1;   b[top]:=1;   fillchar(flag,sizeof(flag),true);   for i:=1 to n+n+2 do d[i]:=maxlongint;   fillchar(pre,sizeof(pre),0);   flag[1]:=false;   pre[1]:=-1;   d[1]:=0;   repeat    for i:=1 to n+n+2 do     if b[top]<>i then      if f[b[top],i]>0 then       if c[b[top],i]+d[b[top]]<d[i] then        begin         d[i]:=c[b[top],i]+d[b[top]];         pre[i]:=b[top];         if flag[i] then begin          tail:=tail+1;          b[tail]:=i;          flag[i]:=false;         end;        end;    flag[b[top]]:=true;    top:=top+1;   until top>tail;   if d[n+n+2]=maxlongint then break;   i:=n+n+2;   min:=maxlongint;   while pre[i]<>-1 do    begin     if min>f[pre[i],i] then min:=f[pre[i],i];     i:=pre[i];    end;   i:=n+n+2;   while pre[i]<>-1 do    begin     f[i,pre[i]]:=f[i,pre[i]]+min;     f[pre[i],i]:=f[pre[i],i]-min;     cost:=cost+c[pre[i],i]*min;     i:=pre[i];    end;    ttf:=ttf+min;//    writeln(cost);   end;  writeln(cost*cost);//  writeln(ttf); end; readln;readln;end.

加一个源点连向所有左边的点，加一个汇点连向所有右边的点，边的费用为0，流量为1。

中间的边费用为c，流量为1

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