bzoj3926[Zjoi2015]诸神眷顾的幻想乡 广义后缀自动机

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#define fo(i,a,b) for(int i=a;i<=b;i++)
#define fd(i,a,b) for(int i=a;i>=b;i--)
using namespace std;
const int N=5e5+5;
typedef long long ll;
int cnt,tot,n,m,l[N*10],head
,col
,d
;
int go[N*2],next[N*2],ch[N*10][15],fa[N*10];
inline void add(int x,int y)
{
go[++cnt]=y;
next[cnt]=head[x];
head[x]=cnt;
}
int ins(int p,int x)
{
int np,q,nq;
np=++cnt;l[np]=l[p]+1;
for (;!ch[p][x]&&p;p=fa[p]) ch[p][x]=np;
if (!p) fa[np]=1;
else
{
q=ch[p][x];
if (l[q]==l[p]+1) fa[np]=q;
else
{
nq=++cnt;l[nq]=l[p]+1;
memcpy(ch[nq],ch[q],sizeof(ch[q]));
fa[nq]=fa[q];
fa[q]=fa[np]=nq;
for (;ch[p][x]==q;p=fa[p]) ch[p][x]=nq;
}
}
return np;
}
inline void dfs(int x,int fa,int p)
{
int t=ins(p,col[x]);
for(int i=head[x];i;i=next[i])
{
int v=go[i];
if (v!=fa)
dfs(v,x,t);
}
}
int main()
{
scanf("%d%d",&n,&m);
fo(i,1,n)scanf("%d",&col[i]);
fo(i,1,n-1)
{
int x,y;
scanf("%d%d",&x,&y);
add(x,y);
add(y,x);
d[x]++,d[y]++;
}
cnt=1;
fo(i,1,n)if (d[i]==1)dfs(i,0,1);
ll ans=0;
fo(i,1,cnt)ans+=l[i]-l[fa[i]];
printf("%lld\n",ans);
return 0;
}