动物园「NOI2014」

题意

求不相交前后缀匹配数量。

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思路

注意本题求的是数量，不是长度。

代码

#include <bits/stdc++.h>

using namespace std;

namespace StandardIO {

    template<typename T> inline void read (T &x) {
        x=0;T f=1;char c=getchar();
        for (; c<'0'||c>'9'; c=getchar()) if (c=='-') f=-1;
        for (; c>='0'&&c<='9'; c=getchar()) x=x*10+c-'0';
        x*=f;
    }
    template<typename T> inline void write (T x) {
        if (x<0) putchar('-');
        if (x>=10) write(x/10);
        putchar(x%10+'0');
    }

}

using namespace StandardIO;

namespace Solve {
    
    const int N=1000100;
    const int MOD=1000000007;
    
    int n,m,ans;
    char s[N];
    int next[N],num[N];

    inline void MAIN () {
        read(n);
        while (n--) {
            scanf("%s",s+1),m=strlen(s+1),ans=1,num[1]=1;
            for (register int i=2,j=0; i<=m; ++i) {
                while (j&&s[j+1]!=s[i]) j=next[j];
                if (s[j+1]==s[i]) ++j;
                next[i]=j,num[i]=num[j]+1;
            }
            for (register int i=1,j=0; i<=m; ++i) {
                while (j&&s[j+1]!=s[i]) j=next[j];
                if (s[j+1]==s[i]) ++j;
                while (j>i/2) j=next[j];
                ans=(1ll*ans*(num[j]+1))%MOD;
            }
            write(ans),putchar('\n');
        }
    }

}

int main () {
//  freopen(".in","r",stdin);
//  freopen(".out","w",stdout);
    Solve::MAIN();
}