HYSBZ 1601(单点带值的最小生成树)

内容目录

题目大意:最小生成树

建源点0与各点连线的权为建水库的大小。

Program aa;
var
   n,i,j,p:longint;
   u,v,w:array[0..100000] of longint;
   size,cost:longint;
   father:array[0..300] of longint;
procedure qsort(l,r:longint);
var
   i,j,m,p:longint;
begin
   i:=l;j:=r;m:=w[(l+r) shr 1];
   repeat
      while w[i]<m do inc(i);
      while w[j]>m do dec(j);
      if i<=j then
      begin
         p:=w[i];w[i]:=w[j];w[j]:=p;
         p:=u[i];u[i]:=u[j];u[j]:=p;
         p:=v[i];v[i]:=v[j];v[j]:=p;
         inc(i);dec(j);
      end;
   until i>j;
   if l<j then qsort(l,j);
   if i<r then qsort(i,r);
end;
function getfather(x:longint):longint;
begin
   if father[x]=x then exit(x);
   father[x]:=getfather(father[x]);
   exit(father[x]);
end;
begin
   read(n);
   for i:=1 to n do
   begin
      read(w[i]);
      u[i]:=0;v[i]:=i;
   end;
   size:=n;
   for i:=1 to n do
      for j:=1 to n do
      begin
        read(p);
        if i=j then continue;
        inc(size);
        u[size]:=i;v[size]:=j;w[size]:=p;
      end;


   qsort(1,size);

   cost:=0;
   for i:=0 to n do father[i]:=i;
   for i:=1 to size do
   begin
      if (getfather(u[i])<>getfather(v[i])) then
      begin
         inc(cost,w[i]);
         father[getfather(u[i])]:=father[getfather(v[i])];
      end;
   end;


   writeln(cost);


end.