String Challenge (Generic)

Problem Overview

• Compute the minimum number of changes to make every character have an identical adjacent neighbor in the caption.
• Input: a lowercase string 'a'–'z' (length 2 to 1e5); Output: the minimal count of edits.
• Allowed edit: change any letter to its immediate predecessor or successor; 'a' can't go left and 'z' can't go right.
• Real-world context: refining TikTok Academy video captions.
• From TikTok interviews; a coding interview problem and interview question.