weighted_choice_gen.cpp

template<typename Value>
auto weighted_choice_gen(std::vector<Weighted<Value>> const& weighted_values)
{
   auto const& intervals = details::make_intervals(weighted_values);
   double sum_weights = intervals.back().first;
   return [=](std::mt19937& bit_gen) -> Value
   {
      std::uniform_real_distribution<double> distribution(0., sum_weights);
      return details::search_containing_interval(intervals, distribution(bit_gen));
   };
}