19#include <unordered_map>
26 inline std::vector<T> vector_from_set(
const std::set<T> &in) {
28 for (
const T &t : in) {
35 inline std::set<T> set_from_vector(
const std::vector<T> &in) {
37 for (
const T &t : in) {
43 template<
class K,
class T>
44 inline std::vector<K> keys_from_map(
const std::unordered_map<K, T> &in) {
46 for (
const auto &[key, value] : in) {
namespace for basic c++ utilities