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=500010;
int n,m;
struct nod{
    int y,next;
};nod e1[maxn*8];nod e[maxn*8];nod e2[maxn*8];
int head1[maxn]={},head[maxn]={},tot1=0,tot=0;
int head2[maxn]={},tot2=0;
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=0;
    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>=1&&p){
        poi[x]=1;
        bel1[x]=++tn;
    }
    if(!p){
        if(z>1){poi[x]=1;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][30]={},id[maxn]={},shu;
int a[maxn]={},val1[maxn];
void dfs(int x,int p){
    dep[x]=dep[p]+1;fa[x][0]=p;val[x]=val[p]+val1[x];id[x]=++shu;
    //cout<<x<<shu<<endl;
    for(int i=1;i<=20;i++)fa[x][i]=fa[fa[x][i-1]][i-1];
    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=20;i>=0;i--)if(dep[fa[x][i]]>=dep[y])x=fa[x][i];
    if(x==y)return x;
    for(int i=20;i>=0;i--)if(fa[x][i]!=fa[y][i]){x=fa[x][i];y=fa[y][i];}
    return fa[x][0];
}
int dfs2(int x){
    int ans=0;//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]=0;
}
void solve(){
    int nm;scanf("%d",&nm);
    int tly=1,w=0;
    for(int i=1;i<=nm;i++){ scanf("%d",&a[i]); if(poi[a[i]]){a[i]=bel1[a[i]]; }else a[i]=bel[a[i]];}
    sort(a+1,a+1+nm,mcmp);
    for(int i=2;i<=nm;i++)if(a[tly]!=a[i])a[++tly]=a[i];
    tot2=0;tai=1;sta[1]=a[1];w-=val1[a[1]];
    for(int i=2;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==1||(tai>1&&dep[sta[tai-1]]<dep[lc])){
                init2(lc,sta[tai]);tai--;break;
            }
            if(tai-1>0)init2(sta[tai-1],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+1]);}
    w+=dfs2(sta[1]); dfs3(sta[1]);
    //cout<<tly<<' '<<a[1]<<' '<<a[2]<<endl;
    //cout<<sta[1]<<' '<<getlca(a[1],a[2])<<endl;
    w+=val1[sta[1]];
    cout<<w<<endl;
}
int main(){
    //freopen("game.in","r",stdin);
    //freopen("game.out","w",stdout);
    int T;scanf("%d",&T);
    while(T-->0){
        scanf("%d%d",&n,&m);
        memset(dfn,0,sizeof(dfn));
        memset(poi,0,sizeof(poi));
        memset(low,0,sizeof(low));
        memset(bel,0,sizeof(bel));
        memset(bel1,0,sizeof(bel1));
        memset(head1,0,sizeof(head1));
        memset(head2,0,sizeof(head2));
        memset(head,0,sizeof(head));
        memset(fa,0,sizeof(fa));
        memset(val,0,sizeof(val));
        memset(val1,0,sizeof(val1));
        tot1=0,tot2=0,tot=0;cnt=0;tn=0;tai=0;shu=0;
        int x,y;
        for(int i=1;i<=m;i++){scanf("%d%d",&x,&y);if(x==y)continue;init1(x,y);init1(y,x);}
        Tarjan(1,0);for(int i=1;i<=tn;i++)pa[i]=i;
        for(int i=1;i<=n;i++){
            if(poi[i]){
                val1[bel1[i]]=1;
                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=1;i<=n;i++){
            if(poi[i])dfs11(i);
        }
        dfs(1,0);
        int q;scanf("%d",&q);
        for(int i=1;i<=q;i++)solve();
    }
    return 0;
}