[BZOJ4516] [SDOI2016] 生成魔咒 - 后缀数组/后缀自动机

感觉还是SAM比较好写QAQ。

显然ans就是∑len[i]-len[fail[i]]

#include"bits/stdc++.h"
#define mmap map<int,int>::iterator
using namespace std;

const int N=200005;

struct SAM{
map<int,int>e
;long long res;
int len
,fail
,cnt,last,n;
SAM(){cnt=last=1;}
int extend(int c){
int p=last,np=++cnt;len[np]=len[p]+1;
for(;e[p].find(c)==e[p].end()&&p;p=fail[p])
e[p].insert(make_pair(c,np));
if(!p)fail[np]=1;
else {
int q=e[p].find(c)->second,nq;
if(len[q]==len[p]+1)fail[np]=q;
else {
nq=++cnt;len[nq]=len[p]+1;e[nq]=e[q];
fail[nq]=fail[q],fail[q]=fail[np]=nq;
for(mmap i;i=e[p].find(c),i->second==q;p=fail[p])
i->second=nq;
}
}
last=np;
return len[np]-len[fail[np]];
}
void work(){
scanf("%d",&n);int a,i;
for(i=1;i<=n;i++){
scanf("%d",&a);
res+=extend(a);
printf("%lld\n",res);
}
}
} sam;

int main(){
sam.work();
return 0;
}