#include <iostream>
#include <string>
#include <vector>

void print_vector(const std::vector<int> &pos,
                  const std::vector<std::string> &str) {
  for (size_t i = 1; i < pos.size(); ++i) // offset: i:1..N
    printf("%s\t", str[pos[i]].c_str());  // str:      0..N-1
  printf("\n");
}

// idea: custom number system with 2s complement like 0b10...0==MIN stop case
void combination_with_repetiton(int n, int k,
                                const std::vector<std::string> &str) {
  std::vector<int> pos(k + 1, 0);
  while (true) {
    for (int i = k; i > 0; i -= 1) {
      if (pos[i] > n - 1) // if number spilled over: xx0(n-1)xx
      {
        pos[i - 1] += 1; // set xx1(n-1)xx
        for (int j = i; j <= k; j += 1)
          pos[j] = pos[j - 1]; // set xx11..1
      }
    }
    if (pos[0] > 0) // stop condition: 1xxxx
      break;
    print_vector(pos, str);
    pos[k] += 1; // xxxxN -> xxxxN+1
  }
}

int main() {
  std::vector<std::string> str{"iced", "jam", "plain"};
  combination_with_repetiton(3, 2, str);
  return 0;
}