【BZOJ3879】—SvT（后缀自动机+虚树/后缀自动机+单调栈）

传送门

后缀数组终于跑过了$Sam$了

后缀自动机上虚树是显然的
后缀数组就按$rk$排序后考虑每个位置的贡献，显然就是左右都比他大的时候
单调栈维护一下就是了

---

后缀数组+单调栈

#include<bits/stdc++.h>
using namespace std;
const int RLEN=1<<20|1;
inline char gc(){
    static char ibuf[RLEN],*ib,*ob;
    (ib==ob)&&(ob=(ib=ibuf)+fread(ibuf,1,RLEN,stdin));
    return (ib==ob)?EOF:*ib++;
}
inline int read(){
    char ch=gc();
    int res=0,f=1;
    while(!isdigit(ch))f^=ch=='-',ch=gc();
    while(isdigit(ch))res=(res+(res<<2)<<1)+(ch^48),ch=gc();
    return f?res:-res;
}
inline void readstring(char *s){
	int len=0;char c;
	while(isspace(c=gc()));
	while(s[len++]=c,!isspace(c=gc())&&c!=EOF);
}
#define pii pair<int,int>
#define fi first
#define se second
#define re register
#define pb push_back
#define ll long long
inline void file(){
    #ifdef Stargazer
    freopen("lx.cpp","r",stdin);
    #endif
}
const int N=1000005;
namespace Sa{
	int rk[N],sa[N],sa2[N],cnt[N],n,m,s[N],ht[N];
	inline void Sort(){
		for(int i=1;i<=m;i++)cnt[i]=0;
		for(int i=1;i<=n;i++)cnt[rk[sa2[i]]]++;
		for(int i=1;i<=m;i++)cnt[i]+=cnt[i-1];
		for(int i=n;i>=1;i--)sa[cnt[rk[sa2[i]]]--]=sa2[i];
	}
	inline void build(){
		m=30;
		for(int i=1;i<=n;i++)rk[i]=s[i],sa2[i]=i;
		Sort();
		for(int i=1,pos=0;i<=n&&pos<n;i<<=1){
			pos=0;
			for(int j=n-i+1;j<=n;j++)sa2[++pos]=j;
			for(int j=1;j<=n;j++)if(sa[j]>i)sa2[++pos]=sa[j]-i;
			Sort();
			pos=1,swap(sa2,rk);
			rk[sa[1]]=1;
			for(int j=2;j<=n;j++)
				rk[sa[j]]=(sa2[sa[j]]==sa2[sa[j-1]])&&(sa2[sa[j]+i]==sa2[sa[j-1]+i])?pos:++pos;
			m=pos;
		}
		for(int i=1,j,k=0;i<=n;ht[rk[i++]]=k)
		for(k?k--:0,j=sa[rk[i]-1];s[i+k]==s[j+k];k++);
	}
	int st[21][N],lg[N];
	inline void buildst(){
		lg[0]=-1;
		for(int i=1;i<=n;i++)lg[i]=lg[i>>1]+1,st[0][i]=ht[i];
		for(int i=1;(1<<i)<=n;i++)
		for(int j=1;j+(1<<i)-1<=n;j++)
		st[i][j]=min(st[i-1][j],st[i-1][j+(1<<(i-1))]);
	}
	inline int lcp(int x,int y){
		x=rk[x],y=rk[y];
		if(x>y)swap(x,y);x++;
		int t=lg[y-x+1];
		return min(st[t][x],st[t][y-(1<<t)+1]);
	}
}
inline bool comp(int a,int b){
	return Sa::rk[a]<Sa::rk[b];
}
inline void calc(){
	static int a[N],val[N],stk[N],l[N],r[N],top;
	int n=read(),res=0;
	for(int i=1;i<=n;i++)a[i]=read();
	sort(a+1,a+n+1,comp),n=unique(a+1,a+n+1)-a-1;
	for(int i=1;i<n;i++)val[i]=Sa::lcp(a[i],a[i+1]);
	for(int i=1;i<n;i++){
		while(top&&val[stk[top]]>=val[i])r[stk[top--]]=i;
		stk[++top]=i;
	}
	while(top)r[stk[top--]]=n;
	for(int i=n-1;i;i--){
		while(top&&val[stk[top]]>val[i])l[stk[top--]]=i;
		stk[++top]=i;
	}
	while(top)l[stk[top--]]=0;
	for(int i=1;i<n;i++)
	res+=1ll*val[i]*(i-l[i])*(r[i]-i);
	cout<<res<<'
';
}
int n,m;
char s[N];
int main(){
	file();
	n=read(),m=read();
	readstring(s+1);
	Sa::n=strlen(s+1);
	for(int i=1;i<=Sa::n;i++)Sa::s[i]=s[i]-'a'+1;
	Sa::build(),Sa::buildst();
	for(int i=1;i<=m;i++)
	calc();
}

---

后缀自动机+虚树

#include<bits/stdc++.h>
using namespace std;
const int RLEN=1<<20|1;
inline char gc(){
    static char ibuf[RLEN],*ib,*ob;
    (ib==ob)&&(ob=(ib=ibuf)+fread(ibuf,1,RLEN,stdin));
    return (ib==ob)?EOF:*ib++;
}
inline int read(){
    char ch=gc();
    int res=0,f=1;
    while(!isdigit(ch))f^=ch=='-',ch=gc();
    while(isdigit(ch))res=(res+(res<<2)<<1)+(ch^48),ch=gc();
    return f?res:-res;
}
inline void readstring(char *s){
	int len=0;char c;
	while(isspace(c=gc()));
	while(s[len++]=c,!isspace(c=gc())&&c!=EOF);
}
#define pii pair<int,int>
#define fi first
#define se second
#define re register
#define pb push_back
#define ll long long
inline void file(){
    #ifdef Stargazer
    freopen("lx.cpp","r",stdin);
    #endif
}
const int N=1000005;
namespace Sam{
	int nxt[N][26],fa[N],len[N],tot,last;
	inline void insert(int c){
		int cur=++tot,p=last;last=cur;
		len[cur]=len[p]+1;
		for(;p&&!nxt[p][c];p=fa[p])nxt[p][c]=cur;
		if(!p)fa[cur]=1;
		else {
			int q=nxt[p][c];
			if(len[p]+1==len[q])fa[cur]=q;
			else{
				int clo=++tot;
				memcpy(nxt[clo],nxt[q],sizeof(nxt[q]));
				fa[clo]=fa[q],len[clo]=len[p]+1;
				fa[q]=fa[cur]=clo;
				for(;p&&nxt[p][c]==q;p=fa[p])nxt[p][c]=clo;
			}
		}
	}
}
namespace G{
	vector<int> e[N];
	int tot,in[N],out[N],dep[N],top[N],fa[N],siz[N],son[N],pos[N];
	int a[N],vis[N],ok[N],stk[N],tp,T;
	ll ans;
	inline void addedge(int u,int v){
		e[u].pb(v);
	}
	inline bool comp(int a,int b){
		return in[a]<in[b];
	}
	void dfs1(int u){
		siz[u]=1;
		for(int &v:e[u]){
			if(v==fa[u])continue;
			fa[v]=u,dep[v]=dep[u]+1;
			dfs1(v),siz[u]+=siz[v];
			if(siz[v]>siz[son[u]])son[u]=v;
			siz[v]=0;
		}
	}
	void dfs2(int u,int tp){
		in[u]=++tot,top[u]=tp;
		if(son[u])dfs2(son[u],tp);
		for(int &v:e[u]){
			if(v==son[u]||v==fa[u])continue;
			dfs2(v,v);
		}
		out[u]=tot;
		e[u].clear();
	}
	inline int Lca(int u,int v){
		while(top[u]!=top[v]){
			if(dep[top[u]]<dep[top[v]])swap(u,v);
			u=fa[top[u]];
		}
		return dep[u]<dep[v]?u:v;
	}
	void calc(int u){
		siz[u]=ok[u],ok[u]=0;
		for(int &v:e[u]){
			calc(v);
			ans+=1ll*siz[u]*siz[v]*Sam::len[u];
			siz[u]+=siz[v];
		}
		e[u].clear();
	}
	inline void solve(){
		int m=read(),n=0;T++;ans=0;
		memset(siz,0,sizeof(siz));
		for(int i=1;i<=m;i++){
			int p=read();
			if(vis[p]==T)continue;
			vis[p]=T,a[++n]=pos[p],ok[pos[p]]=1;
		}
		sort(a+1,a+n+1,comp);
		stk[tp=1]=1;
		for(int i=1;i<=n;i++){
			int lca=Lca(stk[tp],a[i]);
			while(in[lca]<in[stk[tp]]){
				if(in[lca]>=in[stk[tp-1]]){
					addedge(lca,stk[tp--]);
					if(stk[tp]!=lca)stk[++tp]=lca;
					break;
				}
				addedge(stk[tp-1],stk[tp]),tp--;
			}
			stk[++tp]=a[i];
		}
		while(tp>1)addedge(stk[tp-1],stk[tp]),tp--;
		calc(1);cout<<ans<<'
';
	}
}
int n,m;
char s[N];
int main(){
	file();
	n=read(),m=read();
	readstring(s+1);
	Sam::last=Sam::tot=1;
	for(int i=strlen(s+1);i;i--)Sam::insert(s[i]-'a'),G::pos[i]=Sam::last;
	for(int i=2;i<=Sam::tot;i++)G::addedge(Sam::fa[i],i);
	G::dfs1(1),G::dfs2(1,1);
	for(int i=1;i<=m;i++)
		G::solve();
}