C++ Red belt booking

#include "test_runner.h"
#include <iostream>
#include <string>
#include <cstdint>
#include <map>
#include <deque>

using namespace std;

typedef uint32_t ClientID;
typedef int64_t Time;
typedef uint16_t RoomCount;
typedef string HotelName;

const Time hours_24 = 86400;

struct InputItem {
    Time time;
    HotelName hotel_name;
    ClientID client_id;
    RoomCount room_count;
};

class HotelBase {

    typedef map<ClientID, size_t> ClientMap;
    struct HotelItem {
        ClientMap clients;
        size_t reserved_rooms;
    };
    typedef map<HotelName, HotelItem> HotelMap;

    struct QueueItem {
        QueueItem(Time time, HotelMap::iterator hotel_it,
                ClientMap::iterator client_it, RoomCount room_count) :
                time(time), hotel_it(hotel_it), client_it(client_it), room_count(
                        room_count) {
        }
        Time time;
        HotelMap::iterator hotel_it;
        ClientMap::iterator client_it;
        RoomCount room_count;
    };

public:
    void Book(const InputItem& input);
    size_t Clients(const HotelName& hotel_name) const;
    size_t Rooms(const HotelName& hotel_name) const;

private:
    HotelMap hotels;
    deque<QueueItem> time_queue;
};