#include <iostream>
#include <chrono>
#include <map>
#include <deque>
#include <thread>
#include <algorithm>

int main()
{
    using namespace std;
    deque<int> ids = {4, 7, 0, 7, 1, 0, 1, 2, 1, 2, 6};
    enum { frame_size = 5 };
    typedef map<int, chrono::system_clock::time_point> MAP;
    MAP frame;
    while (!ids.empty())
    {
        int id = ids.front();
        ids.pop_front();
        if (frame.find(id) == frame.end())
        {
            if (frame.size() == frame_size)
            {
                auto it = min_element(frame.begin(), frame.end(),
                    [] (MAP::const_reference left, MAP::const_reference right)
                    {
                        return left.second < right.second;
                    });
                cout << it->first << " was erased\n";
                frame.erase(it);
            }
            frame[id] = chrono::system_clock::now();
        }
        this_thread::sleep_for(chrono::milliseconds(500));
    }
}