1845. Seat Reservation Manager

Design a system that manages the reservation state of n seats that are numbered from 1 to n.

Implement the SeatManager class:

• SeatManager(int n) Initializes a SeatManager object that will manage n seats numbered from 1 to n. All seats are initially available.
• int reserve() Fetches the smallest-numbered unreserved seat, reserves it, and returns its number.
• void unreserve(int seatNumber) Unreserves the seat with the given seatNumber.

class SeatManager {
    priority_queue<int, vector<int>, greater<int>> pq;
    int seat = 1;
public:
    SeatManager(int n) {
        
    }
    
    int reserve() {
        if(pq.empty()) {
            return seat++;
        } else {
            auto s = pq.top(); pq.pop();
            return s;
        }
    }
    
    void unreserve(int seatNumber) {
        if(seatNumber + 1 == seat) {
            seat--;
        } else {
            pq.push(seatNumber);
        }
    }
};

/**
 * Your SeatManager object will be instantiated and called as such:
 * SeatManager* obj = new SeatManager(n);
 * int param_1 = obj->reserve();
 * obj->unreserve(seatNumber);
 */