Who is the smartest Superhero/villain?

I will deliberately leave it to you to determine what 'smartest' means. Who do you think is the smartest and why?

Candidates:

Bruce Wayne

Lex Luthor

Darkseid

Thanos

Dr. Doom

Reed Richards

Other (please list who you think is the smartest)

Thanos

Thanos.

Alexander Luthor Junior

Doom

Brainaic 5

Or if you want to get technical with a person who has absolutely no feats Brainiac 417

Bats.