kmp

using namespace std;
#define MAXN 1000000
#define MAXM 100000
int T[MAXN],P[MAXM],Next[MAXM];

void (int M)
{
    Next[0] = -1;
    int i = 0, j = -1;
    while(i<M)
	{
        if(j==-1 || P[i]==P[j])
		{
            i++,j++;
            if(P[i]!=P[j])
				Next[i] = j;
            else
				Next[i] = Next[j];
        }
        else
			j = Next[j];
    }
}

int KMP(int N,int M)//进行匹配
{
    int i=0,j=0;
    while(i<N && j<M)
	{
        if(T[i]==P[j] || j==-1)
			i++,j++;
        else
			j = Next[j];
    }
    if(j==M)
		return i-M+1;
    else
		return -1;
}
int main()
{
    int N,M,C;
    scanf("%d",&C);
    while(C--)
	{
		int i;
        scanf("%d %d",&N,&M);
        for(i=0;i<N;i++)
			scanf("%d",&T[i]);
        for(i=0;i<M;i++)
			scanf("%d",&P[i]);
        if(M>N)
			printf("-1n");
        else
		{
            MakeNext(M);
            printf("%dn",KMP(N,M));
        }
    }
    return 0;
}