[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[N];long long res;
	int len[N],fail[N],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;
}