CareerCup

#include <iostream>
#include <queue>
#include <thread>
#include <atomic>

class TwitterTag 
{
    unsigned long _last_24hr_count{0};
    std::queue<unsigned int> _per_min_count;
    std::atomic<unsigned int> _last_1min_count{1u};

    public:

    void mention()
    {
        _last_1min_count++;
    }

    void Start()
    {
        while (true)
        {
            if(_per_min_count.size() >= 60*24 /*number of min in 24 hrs*/)
            {
                _per_min_count.push(_last_1min_count);
                _last_24hr_count += _last_1min_count;
                _last_1min_count=0;
                auto earliest_count = _per_min_count.front();
                _last_24hr_count -= earliest_count;
                _per_min_count.pop();
            }
            std::this_thread::sleep_for(std::chrono::minutes(1));
        }
    }

    const TwitterTag& instance()
    {
        static TwitterTag _instance;
        static std::thread _thread([this]{Start();});
        return _instance;
    }

    bool istrending()/*if last 24 hour mention is more than 100000, it is trending*/
    {
        return _last_24hr_count>100000ul;
    }
};


int main()
{
    return 0;
}