int lengthOfLIS(vector<int>& nums) {
        vector<int> last_indices;

        for (int i = 0; i < nums.size(); ++i) {
            auto first_greater_or_eq = lower_bound(last_indices.begin(), last_indices.end(), nums[i]);
            if (first_greater_or_eq == last_indices.end()) last_indices.push_back(nums[i]);
            else *first_greater_or_eq = nums[i];
        }

        return last_indices.size();
    }