Mi_Question

main.cpp

#include<iostream>

// slot choice    result
// 1    3         3
// 2    3         1 3
//                2 2
//                3 1


int f(int slot, int choice) {
  int result = 0;
  if (slot == 1) return choice;
  for (int i = 0; i < choice; i++) {
    result += f(slot - 1, choice - i);
  }
  return result;
}

int main() {
  std::cout << "slot\tchoice\t" << std::endl;
  std::cout << "1\t1\t" << f(1, 1) << std::endl;
  std::cout << "1\t2\t" << f(1, 2) << std::endl;
  std::cout << "1\t3\t" << f(1, 3) << std::endl;
  std::cout << "2\t3\t" << f(2, 3) << std::endl;
  std::cout << "3\t3\t" << f(3, 3) << std::endl;
  std::cout << "4\t4\t" << f(4, 4) << std::endl;

  return 0;
}