hdu3336Count the string

#include <stdio.h>
#include<cstring>
#include<iostream>
using namespace std;
int lb;
char b[200010];
int nxt[200010];
int dp[200010];
void gnx(){
int i=0,j=-1;
nxt[0]=-1;
while(i<lb){
if(j==-1||b[i]==b[j])nxt[++i]=++j;
else j=nxt[j];
}
}
int main(void)
{
int t;
scanf("%d",&t);
while(t--){
scanf("%d",&lb);
scanf("%s",b);
memset(dp,0,sizeof(dp));
gnx();
int sum=0;
for(int i=1;i<=lb;i++){
if(nxt[i]==-1)dp[i]=1;
else dp[i]+=(dp[nxt[i]]+1);
dp[i]%=10007;
sum+=dp[i];
sum%=10007;
}
printf("%d\n",sum);
}
return 0;
}