[HDU 3336]Count the String[kmp]

#include <cstdio>
using namespace std;
const int MAXW = 200005;
const int MOD = 10007;
char W[MAXW];
int n;
int next[MAXW];
void prekmp(char *B, int *next)
{
int j = -1;
next[0] = -1;
for(int i=1; B[i]; i++)
{
while(j != -1 && B[j+1] != B[i]) j = next[j];
if(B[i] == B[j+1]) j++;
next[i] = j;
}
/*for(int i=0;i<n;i++)
printf("next[%d] %d\n",i,next[i]);*/
}

int kmp(char *B, int *next)
{
long long ret = 0;
for(int i=0; B[i]; i++)
{
ret++;
int tmp = next[i];
while(tmp!=-1)
{
ret++;
tmp = next[tmp];
}
ret %= MOD;
}
return ret;
}

int main()
{
int cas;
scanf("%d",&cas);
while(cas--)
{
scanf("%d",&n);
scanf("%s",W);
prekmp(W,next);
printf("%d\n",kmp(W,next));
}
}