Memoized, recursive factorial function?

Question

I know how to do memoization in Python easily but I need a faster way to compute them, so I am using C++. However, I have no clue how to memoize. I understand that it\'s abo

Answer 1

I like relying on lambda capture as in (uses std=c++14)

template
auto memoize(std::function&& f)
{
  using F = std::function;
  std::map,R> cache;
  return ([cache = std::map,R>{}, 
           f = std::forward(f)](Args&&... args) mutable
    {
      std::tuple t(args...);
      if (cache.find(t) == cache.end())
        {
          R r = f(std::forward(args)...);
          cache[t] = r;
        }
      return cache[t];
    });
}