Another branch of optimism that solves the problem of evil would be Instumentalistic Optimism. This says that every single instance of evil results in an instance of good in the long run.
This was what Candide expressed throughout the most of the story. The Lisbon Earthquake, the big storm while they were on the sea, and the Bulgarian/Abarian War was supposed to happen in this world because this is "the best of all possible worlds”