int binary_search_last_occurrence(const vector<int>& lst, int target) {
    if (lst.empty()) return -1;

    int low = 0, high = lst.size() - 1;

    while (low < high) {
        int mid = (low + high + 1) / 2;
        if (lst[mid] <= target) {
            low = mid;
        } else {
            high = mid - 1;
        }
    }

    if (lst[low] == target)
        return low;
    else
        return -1;
}