Luogu P2375 [NOI2014]动物园

Luogu P2375 [NOI2014]动物园

解析

• KMP 的神奇应用

Code

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define LL long long
using namespace std;
const int N=1e6+5;
const LL mod=1e9+7;
int n,p[N];
char ch[N];
LL ans,num[N];
LL kmp(char s[])
{
	int j=0,len=strlen(s+1);
	num[1]=1;
	for(int i=1;i<len;i++)
	{
		while(j!=0&&s[i+1]!=s[j+1]) j=p[j];
		if(s[i+1]==s[j+1]) j++;
		p[i+1]=j;
		num[i+1]=num[p[i+1]]+1;
	}
	j=0;
	LL res=1;
	for(int i=1;i<len;i++)
	{
		while(j!=0&&s[i+1]!=s[j+1]) j=p[j];
		if(s[i+1]==s[j+1]) j++;
		while(j>((i+1)>>1)) j=p[j];
		res=(res*(num[j]+1))%mod;
	}
	return res;
}
int main()
{
	scanf("%d",&n);
	while(n--)
	{
		cin>>(ch+1);
		ans=kmp(ch);
		printf("%lld
",ans);
	}
	return 0;
}