Reverse Alphanumeric Segments

Problem Overview For a supplied string, reverse each longest contiguous block made up only of English letters or digits. All remaining characters, including whitespace, punctuation marks, and apostrophes, must remain where they are. Sample Cases The apostrophe in We're is a non-alphanumeric separator. Consequently, We becomes eW, while re becomes er, producing eW'er. Notes Treat punctuation as a boundary: We're turns into eW'er, rather than er'eW. Numbers belong to…