bzoj3926: [Zjoi2015]诸神眷顾的幻想乡

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <algorithm>
 #define maxn 100005
 #define maxl 200005
 #define maxm 4000005
 using namespace std;

 typedef long long ll;
 int n,c,cnt,tot,root,last,fa[maxm],du[maxn],dist[maxm],son[maxl],prep[maxl],now[maxn],v[maxn];
 ll ans;
 void add(int x,int y){
     cnt++,prep[cnt]=now[x],now[x]=cnt,son[cnt]=y;
 }
 struct Tsegment{
     int son[maxm][];
     void prepare(){tot=last=root=;memset(dist,,sizeof(dist));}
     int newnode(int x){dist[++tot]=x; return tot;}
     int add(int x,int p){
         int q=son[p][x];
         if (q==){
             int np=newnode(dist[p]+); last=np;
             for (;p&&!son[p][x];p=fa[p]) son[p][x]=np;
             if (p==) fa[np]=root;
             else{
                 q=son[p][x];
                 if (dist[p]+==dist[q]) fa[np]=q;
                 else{
                     int nq=newnode(dist[p]+);
                     memcpy(son[nq],son[q],sizeof(son[q]));
                     fa[nq]=fa[q],fa[q]=fa[np]=nq;
                     for (;p&&son[p][x]==q;p=fa[p]) son[p][x]=nq;
                 }
             }
         }else{
             if (dist[p]+==dist[q]) last=q;
             else{
                 int nq=newnode(dist[p]+); last=nq;
                 memcpy(son[nq],son[q],sizeof(son[q]));
                 fa[nq]=fa[q],fa[q]=nq;
                 for (;p&&son[p][x]==q;p=fa[p]) son[p][x]=nq;
             }
         }
         return last;
     }
 }SAM;
 void dfs(int x,int pa,int goal){
     int p=SAM.add(v[x],goal);
     for (int i=now[x],so=son[i];i;i=prep[i],so=son[i]){
         if (so==pa) continue;
         dfs(so,x,p);
     }
 }
 int main(){
     scanf("%d%d",&n,&c);
     memset(du,,sizeof(du));
     cnt=tot=ans=,memset(now,,sizeof(now));
     for (int i=;i<=n;i++) scanf("%d",&v[i]);
     for (int u,v,i=;i<n;i++) scanf("%d%d",&u,&v),add(u,v),add(v,u),du[u]++,du[v]++;
     SAM.prepare();
     for (int i=;i<=n;i++){
         if (du[i]>) continue;
         dfs(i,,root);
     }
     ans=;
     dist[root]=;
     for (int i=;i<=tot;i++) ans+=(dist[i]-dist[fa[i]]);
     printf("%lld\n",ans);
     return ;
 }

做法：广义后缀自动机模板题。

dfs+后缀自动机。