Luogu P4606 [SDOI2018] 战略游戏 圆方树 虚树

https://www.luogu.org/problemnew/show/P4606

把原来的图的点双联通分量缩点（每个双联通分量建一个点，每个割点再建一个点）（用符合逻辑的方式）建一棵树（我最开始建的想法就有问题，答案竟然还差不多，查了好久才发现……然后重新想了个正确的建法发现比之前那个错误的建法好写多了，气），然后把这棵树整成虚树再做个树上dp就（安排得）明明白白的了。dp的时候注意一下树的根的值也要统计。

我的程序大概常数太大了洛谷开O2才能过，BZOJ会tle，也不想改了，就这样吧……

 #include<iostream>
 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<cmath>
 using namespace std;
 const int maxn=;
 int n,m;
 struct nod{
     int y,next;
 };nod e1[maxn*];nod e[maxn*];nod e2[maxn*];
 int head1[maxn]={},head[maxn]={},tot1=,tot=;
 int head2[maxn]={},tot2=;
 int dfn[maxn]={},low[maxn]={},bel[maxn]={},bel1[maxn]={},poi[maxn]={},sta[maxn]={},tai,cnt,tn;
 int val[maxn]={};
 int pa[maxn]={};
 void init1(int x,int y){ e1[++tot1].y=y;e1[tot1].next=head1[x];head1[x]=tot1; }
 void init(int x,int y){ e[++tot].y=y;e[tot].next=head[x];head[x]=tot; }
 void init2(int x,int y){ e2[++tot2].y=y;e2[tot2].next=head2[x];head2[x]=tot2; }
 int getpa(int x){return x==pa[x]?x:getpa(pa[x]);}
 void merpa(int x,int y){
     x=getpa(x);y=getpa(y);
     pa[x]=pa[y];
 }
 void Tarjan(int x,int p){
     dfn[x]=low[x]=++cnt;sta[++tai]=x; int z=;
     for(int i=head1[x];i;i=e1[i].next){
         if(e1[i].y==p)continue;
         if(!dfn[e1[i].y]){
             Tarjan(e1[i].y,x);
             low[x]=min(low[e1[i].y],low[x]);
             if(low[e1[i].y]>=dfn[x]){
                 int w; ++tn;++z;
                 if(low[e1[i].y]==dfn[x]&&!p)bel[x]=tn;
                 do{
                     w=sta[tai--];
                     bel[w]=tn;
                 }while(w!=e1[i].y);
             }
         }
         else low[x]=min(low[x],dfn[e1[i].y]);
     }
     if(z>=&&p){
         poi[x]=;
         bel1[x]=++tn;
     }
     if(!p){
         if(z>){poi[x]=;bel1[x]=++tn;}
         if(!bel[x])bel[x]=++tn;
     }
 }
 void dfs1(int x){
     for(int i=head1[x];i;i=e1[i].next){
         int y=e1[i].y;
         if(poi[y]){
             if(getpa(bel1[y])!=getpa(bel[x])){
                 init(bel1[y],bel[x]);init(bel[x],bel1[y]);
                 merpa(bel1[y],bel[x]);
             }
         }
     }
 }
 void dfs11(int x){
     for(int i=head1[x];i;i=e1[i].next){
         int y=e1[i].y;
         if(poi[y]){
             if(getpa(bel1[y])!=getpa(bel1[x])){
                 init(bel1[y],bel1[x]);init(bel1[x],bel1[y]);
                 merpa(bel1[y],bel1[x]);
             }
         }
     }
 }
 int dep[maxn]={},fa[maxn][]={},id[maxn]={},shu;
 int a[maxn]={},val1[maxn];
 void dfs(int x,int p){
     dep[x]=dep[p]+;fa[x][]=p;val[x]=val[p]+val1[x];id[x]=++shu;
     //cout<<x<<shu<<endl;
     for(int i=;i<=;i++)fa[x][i]=fa[fa[x][i-]][i-];
     for(int i=head[x];i;i=e[i].next){
         if(e[i].y==p)continue;
         dfs(e[i].y,x);
     }
 }
 bool mcmp(int x,int y){
     return id[x]<id[y];
 }
 int getlca(int x,int y){
     if(dep[x]<dep[y])swap(x,y);
     if(dep[x]!=dep[y])for(int i=;i>=;i--)if(dep[fa[x][i]]>=dep[y])x=fa[x][i];
     if(x==y)return x;
     for(int i=;i>=;i--)if(fa[x][i]!=fa[y][i]){x=fa[x][i];y=fa[y][i];}
     return fa[x][];
 }
 int dfs2(int x){
     int ans=;//cout<<x<<endl;
     for(int i=head2[x];i;i=e2[i].next){//cout<<x<<e2[i].y<<endl;
         ans+=dfs2(e2[i].y);
         ans+=val[e2[i].y]-val[x];
     }
     return ans;
 }
 void dfs3(int x){
     for(int i=head2[x];i;i=e2[i].next){
         dfs3(e2[i].y);
     }head2[x]=;
 }
 void solve(){
     int nm;scanf("%d",&nm);
     int tly=,w=;
     for(int i=;i<=nm;i++){ scanf("%d",&a[i]); if(poi[a[i]]){a[i]=bel1[a[i]]; }else a[i]=bel[a[i]];}
     sort(a+,a++nm,mcmp);
     for(int i=;i<=nm;i++)if(a[tly]!=a[i])a[++tly]=a[i];
     tot2=;tai=;sta[]=a[];w-=val1[a[]];
     for(int i=;i<=tly;i++){
         int lc=getlca(sta[tai],a[i]);w-=val1[a[i]];//cout<<a[i]<<sta[tai]<<lc<<endl;
         while(tai&&dep[lc]<dep[sta[tai]]){
             if(tai==||(tai>&&dep[sta[tai-]]<dep[lc])){
                 init2(lc,sta[tai]);tai--;break;
             }
             if(tai->)init2(sta[tai-],sta[tai]);
             tai--;
         }
         if(sta[tai]!=lc||!tai)sta[++tai]=lc;
         if(sta[tai]!=a[i]||!tai)sta[++tai]=a[i];
     }
     while(--tai){init2(sta[tai],sta[tai+]);}
     w+=dfs2(sta[]); dfs3(sta[]);
     //cout<<tly<<' '<<a[1]<<' '<<a[2]<<endl;
     //cout<<sta[1]<<' '<<getlca(a[1],a[2])<<endl;
     w+=val1[sta[]];
     cout<<w<<endl;
 }
 int main(){
     //freopen("game.in","r",stdin);
     //freopen("game.out","w",stdout);
     int T;scanf("%d",&T);
     while(T-->){
         scanf("%d%d",&n,&m);
         memset(dfn,,sizeof(dfn));
         memset(poi,,sizeof(poi));
         memset(low,,sizeof(low));
         memset(bel,,sizeof(bel));
         memset(bel1,,sizeof(bel1));
         memset(head1,,sizeof(head1));
         memset(head2,,sizeof(head2));
         memset(head,,sizeof(head));
         memset(fa,,sizeof(fa));
         memset(val,,sizeof(val));
         memset(val1,,sizeof(val1));
         tot1=,tot2=,tot=;cnt=;tn=;tai=;shu=;
         int x,y;
         for(int i=;i<=m;i++){scanf("%d%d",&x,&y);if(x==y)continue;init1(x,y);init1(y,x);}
         Tarjan(,);for(int i=;i<=tn;i++)pa[i]=i;
         for(int i=;i<=n;i++){
             if(poi[i]){
                 val1[bel1[i]]=;
                 if(getpa(bel[i])!=getpa(bel1[i])){init(bel[i],bel1[i]);init(bel1[i],bel[i]);merpa(bel1[i],bel[i]);}
             }else dfs1(i);
             /*cout<<bel[i]<<bel1[i]<<poi[i]<<endl;*/
         }
         for(int i=;i<=n;i++){
             if(poi[i])dfs11(i);
         }
         dfs(,);
         int q;scanf("%d",&q);
         for(int i=;i<=q;i++)solve();
     }
     return ;
 }