int removeDuplicates(vector<int>& nums) {
        set<int> s;
        for(int i=0;i<nums.size();++i)
        {
            s.insert(nums[i]);
        }
        set<int> :: iterator it;
        vector<int> v;
        for(it=s.begin();it!=s.end();++it)
        {
            v.push_back(*it);
        }
        nums=v;
        int a = s.size();
        return a;
        
    }