chocolate_feast.cpp

#include <iostream>
#include <limits>
#include <sstream>
#include <string>
#include <vector>

int main() {
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

    for (std::string line; std::getline(std::cin, line);) {
        std::istringstream iss(line);

        int money, price_per_chocolate, num_wrappers_per_free_piece;
        iss >> money >> price_per_chocolate >> num_wrappers_per_free_piece;
        if (!iss)
            continue;

        // Just copy the constraints literally.
        if (money < 2 || money > 100'000)
            continue;

        if (price_per_chocolate < 1 || money < price_per_chocolate)
            continue;

        if (num_wrappers_per_free_piece < 2 || num_wrappers_per_free_piece > money)
            continue;

        int num_chocolates = 0;

        while (money >= price_per_chocolate) {
          money -= price_per_chocolate;
          num_chocolates++;
          if (num_chocolates % num_wrappers_per_free_piece == 0) {
            num_chocolates++;
          }
        }
        std::cout << num_chocolates << std::endl;
    }
}