【NOI2014】动物园

题面

https://www.luogu.org/problem/P2375

题解

// luogu-judger-enable-o2
#include<cstdio>
#include<iostream>
#include<cstring>
#define ri register int
#define N 1000050
#define mod 1000000007
using namespace std;
int T,nex[N],sum[N];
char s[N];
int main(){
  scanf("%d",&T);
  for (ri ti=1;ti<=T;ti++) {
    scanf("%s",s+1);
    int l=strlen(s+1);
    nex[0]=nex[1]=0;
    for (ri i=2;i<=l;i++) {
      int j=nex[i-1];
      while (j && s[j+1]!=s[i]) j=nex[j];
      if (s[j+1]==s[i]) nex[i]=j+1; else nex[i]=0;
    }
    sum[0]=0;
    for (ri i=1;i<=l;i++) sum[i]=sum[nex[i]]+1;
    int j=0;
    long long ans=1LL;
    for (ri i=1;i<=l;i++) {
      while (s[j+1]!=s[i] && j) j=nex[j];
      if (s[j+1]==s[i]) {
        j++;
        while (j*2>i) j=nex[j];
        (ans*=(sum[j]+1))%=mod;
      }
      else j=0;
    }
    printf("%lld
",ans);
  }
}