bzoj3611

会构建虚树之后就是noip提高组的题目了
稍微难一点的是求代价和，只要注意按一个方向避免重复计算贡献即可

 const inf=;
 type node=record
        po,next:longint;
      end;

 var mi,mx,fa,p,q,size,d,a,b:array[..] of longint;
     e:array[..] of node;
     f:array[..] of int64;
     v:array[..] of boolean;
     anc:array[..,..] of longint;
     ans2,ans3,z,t,h,i,len,n,m,s,j,x,y:longint;
     dis,ans1:int64;

 procedure add(x,y:longint);
   begin
     inc(len);
     e[len].po:=y;
     e[len].next:=p[x];
     p[x]:=len;
   end;

 procedure swap(var a,b:longint);
   var c:longint;
   begin
     c:=a;
     a:=b;
     b:=c;
   end;

 function max(a,b:longint):longint;
   begin
     if a>b then exit(a) else exit(b);
   end;

 function min(a,b:longint):longint;
   begin
     if a>b then exit(b) else exit(a);
   end;

 procedure dfs(x:longint);
   var i,y:longint;
   begin
     inc(h);
     a[x]:=h;
     i:=p[x];
     while i<> do
     begin
       y:=e[i].po;
       if fa[x]<>y then
       begin
         fa[y]:=x;
         anc[y,]:=x;
         d[y]:=d[x]+;
         dfs(y);
       end;
       i:=e[i].next;
     end;
   end;

 procedure sort(l,r:longint);
   var i,j,x:longint;
   begin
     i:=l;
     j:=r;
     x:=a[b[(l+r) shr ]];
     repeat
       while a[b[i]]<x do inc(i);
       while x<a[b[j]] do dec(j);
       if not(i>j) then
       begin
         swap(b[i],b[j]);
         inc(i);
         dec(j);
       end;
     until i>j;
     if l<j then sort(l,j);
     if i<r then sort(i,r);
   end;

 function lca(x,y:longint):longint;
   var i,p:longint;
   begin
     if x=y then exit(x);
     if d[x]<d[y] then swap(x,y);
     p:=trunc(ln(d[x])/ln());
     if d[x]>d[y] then
       for i:=p downto  do
         if d[x]- shl i>=d[y] then x:=anc[x,i];
     if x=y then exit(x);
     for i:=p downto  do
       if (anc[y,i]<>anc[x,i]) then
       begin
         x:=anc[x,i];
         y:=anc[y,i];
       end;
     exit(fa[x]);
   end;

 procedure dp(x:longint);
   var i,y:longint;
   begin
     f[x]:=;
     if v[x] then
     begin
       size[x]:=;  //size[]表示虚树中包含的关键点个数
       mi[x]:=;
       mx[x]:=;
     end
     else begin
       size[x]:=;
       mi[x]:=inf;
       mx[x]:=-inf;
     end;
     i:=p[x];
     while i<> do
     begin
       y:=e[i].po;
       dp(y);
       dis:=d[y]-d[x];
       ans1:=ans1+(f[x]+int64(size[x])*dis)*int64(size[y])+f[y]*int64(size[x]);
       size[x]:=size[x]+size[y];
       f[x]:=f[x]+f[y]+int64(size[y])*dis;
       ans2:=min(ans2,mi[x]+dis+mi[y]);
       ans3:=max(ans3,mx[x]+dis+mx[y]);
       mx[x]:=max(mx[x],dis+mx[y]);
       mi[x]:=min(mi[x],dis+mi[y]);
       i:=e[i].next;
     end;
     p[x]:=;
   end;

 begin
   readln(n);
   for i:= to n- do
   begin
     readln(x,y);
     add(x,y);
     add(y,x);
   end;
   dfs();
   t:=trunc(ln(n)/ln());
   for  i:= to t do
     for j:= to n do
     begin
       y:=anc[j,i-];
       if  y<> then anc[j,i]:=anc[y,i-];
     end;
   fillchar(p,sizeof(p),);
   readln(m);
   for i:= to m do
   begin
     readln(s);
     for j:= to s do
     begin
       read(b[j]);
       v[b[j]]:=true;
     end;
     readln;
     sort(,s);
     ans1:=;
     ans2:=inf;
     ans3:=;
     len:=;
     t:=;
     q[]:=;
     for j:= to s do
     begin
       x:=b[j];
       z:=lca(x,q[t]);
       while d[z]<d[q[t]] do
       begin
         if d[z]>=d[q[t-]] then
         begin
           add(z,q[t]);
           dec(t);
           if q[t]<>z then
           begin
             inc(t);
             q[t]:=z;
           end;
           break;
         end;
         add(q[t-],q[t]);
         dec(t);
       end;
       if q[t]<>x then
       begin
         inc(t);
         q[t]:=x;
       end;
     end;
     while t> do
     begin
       add(q[t-],q[t]);
       dec(t);
     end;
     dp();
     writeln(ans1,' ',ans2,' ',ans3);
     for j:= to s do
       v[b[j]]:=false;
   end;
 end.