Does anybody know how to count the number of subarrays within a bigger array using recursion?

For example if int[] a = {1,2,1,3,1,2,1,1,2}, and int[] b = {1,2}, the correct answer is 3.
This is the only recursive call I have, but I’m not sure what to do beyond this… I know the base case should be if(a.length < b.length), but I don’t understand how to count the occurrences…

return numSubstring(a,b,low, mid-1) + numSubstring(a,b, mid+1,high);

>Solution :

public static int countSubs(int [] data, int [] sub) {
    int cnt = 0;
    if (data.length < sub.length) {
        return cnt;
    }
    boolean found = true;
    for (int i = 0; i < sub.length; i++) {
        if (data[i] != sub[i]) {
            found = false;
            break;
        }
    }
    if (found) {
        cnt++;
    }
    
    cnt += countSubs(Arrays.copyOfRange(data, 1, data.length), sub);
    return cnt;
}