#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <iostream>
#include <thread>
#include <set>

int serve_requests(int current_pos, std::set<int> requests) {
    std::cout << "starting at " << current_pos << std::endl;
    std::cout << "requests:";
    for (int request : requests) {
        std::cout << " " << request;
    }
    std::cout << std::endl;

    auto nearest_request = requests.lower_bound(current_pos);

    while(nearest_request != requests.end()) {
        auto completed_request = nearest_request;
        nearest_request++;

        std::cout << "completed request " << *completed_request << " distance: " << (*completed_request - current_pos) << std::endl;
        current_pos = *completed_request;
        requests.erase(completed_request);
    }

    nearest_request--;
    std::cout << "changing direction" << std::endl;

    while(!requests.empty()) {
        auto completed_request = nearest_request;
        if(nearest_request != requests.begin()) {
            nearest_request--;
        }

        std::cout << "completed request " << *completed_request << " distance: " << (current_pos - *completed_request) << std::endl;
        current_pos = *completed_request;
        requests.erase(completed_request);
    }
    return current_pos;
}

int main() {
    std::set requests = {1, 3, 4, 5, 7, 10, 11, 25, 30, 31, 33, 41};
    serve_requests(12, requests);
}