hdu1711 number sequence

using namespace std;
void (int *pat, int len, int *fail){
    fail[0] = -1;
    for(int i = 1, j = -1; i < len; ++i){
        while(j > -1 && pat[i] != pat[j + 1])
            j = fail[j];
        if(pat[i] == pat[j + 1])
            fail[i] = ++j;
        else
            fail[i] = -1;
    }
}
int KMP_match(int *text, int l1, int *pat, int l2, int *fail){
    for(int i = 0, j = -1; i < l1; ++i){
        while(j > -1 && text[i] != pat[j + 1])
            j = fail[j];
        if(text[i] == pat[j + 1])
            j++;
        if(j == l2 - 1)
            return i - l2 + 2;
    }
    return -1;
}
int n, m, a[1000005], b[10005], fail[10005] = {0};
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &n, &m);
        for(int i = 0; i < n; ++i) scanf("%d", &a[i]);
        for(int i = 0; i < m; ++i) scanf("%d", &b[i]);
        build_fail(b, m, fail);
        printf("%dn", KMP_match(a, n, b, m, fail));
    }
    return 0;
}