线性规划与网络流24题 运输问题（最裸的费用流了）

存费用流模板

用sfpa算出最小费用和路径，沿这条路径增广

const
        inf=maxlongint;
var
        n,m:longint;
        map,a,w:array[0..120,0..120]of longint;

procedure init;
var
        i,j:longint;
begin
        read(m,n);
        for i:=1 to m do
          read(map[0,i]);
        for i:=1 to n do
          read(map[m+i,n+m+1]);
        for i:=1 to m do
          for j:=1 to n do
            begin
              read(w[i,m+j]);
              w[m+j,i]:=-w[i,m+j];
              map[i,m+j]:=inf;
            end;
end;

var
        flag,d,dis,pre:array[0..120]of longint;
        time:longint;

function spfa:boolean;
var
        i,head,tail,num:longint;
begin
        head:=1;
        tail:=1;
        num:=1;
        inc(time);
        for i:=1 to n+m+1 do
          dis[i]:=inf;
        dis[0]:=0;
        d[1]:=0;
        flag[0]:=time;
        while num>0 do
          begin
                for i:=1 to n+m+1 do
                  if (a[d[head],i]>0)and(dis[d[head]]+w[d[head],i]<dis[i]) then
                  begin
                        dis[i]:=dis[d[head]]+w[d[head],i];
                        pre[i]:=d[head];
                        if flag[i]<>time then
                        begin
                          flag[i]:=time;
                          inc(num);
                          tail:=tail mod(n+m+1)+1;
                          d[tail]:=i;
                        end;
                  end;
                flag[d[head]]:=time-1;
                head:=head mod(n+m+1)+1;
                dec(num);
          end;
        if dis[n+m+1]=inf then exit(false);
        exit(true);
end;

procedure work;
var
        i,j,aug,ans:longint;
begin
        for i:=0 to n+m+1 do
          for j:=0 to n+m+1 do
            a[i,j]:=map[i,j];
        ans:=0;
        while spfa do
          begin
            aug:=inf;
            i:=n+m+1;
            while i<>0 do
              begin
                j:=pre[i];
                if a[j,i]<aug then aug:=a[j,i];
                i:=j;
              end;
            inc(ans,dis[n+m+1]*aug);
            i:=n+m+1;
            while i<>0 do
              begin
                j:=pre[i];
                inc(a[i,j],aug);
                dec(a[j,i],aug);
                i:=j;
              end;
          end;
        writeln(ans);
        ans:=0;
        for i:=1 to m do
          for j:=1 to n do
            begin
              w[i,j+m]:=-w[i,j+m];
              w[j+m,i]:=-w[j+m,i];
            end;
        for i:=0 to n+m+1 do
          for j:=0 to n+m+1 do
            a[i,j]:=map[i,j];
        ans:=0;
        while spfa do
          begin
            aug:=inf;
            i:=n+m+1;
            while i<>0 do
              begin
                j:=pre[i];
                if a[j,i]<aug then aug:=a[j,i];
                i:=j;
              end;
            inc(ans,dis[n+m+1]*aug);
            i:=n+m+1;
            while i<>0 do
              begin
                j:=pre[i];
                inc(a[i,j],aug);
                dec(a[j,i],aug);
                i:=j;
              end;
          end;
        writeln(-ans);
end;

begin
    assign(input,'trans.in');
    reset(input);
    assign(output,'trans.out');
    rewrite(output);
        init;
        work;
    close(input);
    close(output);
end.