hdu3336

http://acm.hdu.edu.cn/showproblem.php?pid=3336

#include <iostream>#include <cstdio>#include <cstring>using namespace std;int next[200005];char str[200005];void get_next(char *str,int n){    int i,j;    next[0]=-1;    i=0;j=-1;    while(i<n)    {        if(j==-1||str[i]==str[j])            i++,j++,next[i]=j;        else            j=next[j];    }}int main(){    int t;    scanf("%d",&t);    while(t--)    {        int n;        scanf("%d",&n);        scanf("%s",str);        get_next(str,n);        int i,s=0;        for(i=1;i<=n;i++)        {            if(next[i]!=0)  //next[i]表示前缀等于后缀的最大长度，需仔细理解kmp算法                s++;            if(s>10007)                s=s%10007;        }        s=s+n;        s=s%10007;        printf("%d\n",s);    }    return 0;}