int removeDuplicates(vector<int>& nums) {
    if (nums.size() == 0)
    {
        return 0;
    }
    auto start = nums.begin(), end = nums.end();
    int last_value = *(nums.end() - 1);
    for (auto it = nums.begin(); it != end;)
    {
        int find_value = *it;
        auto upper = upper_bound(start, end, find_value); //Find the last occurring index of this number
        iter_swap(start, it);
        ++start;
        if ((upper != end) || ((upper == end) && (find_value == last_value)))
        {
            it = upper;
        }
        else
        {
            ++it;
        }
    }
    return distance(nums.begin(), start);
}