Prepare Notification

Problem Overview

• Task: Create a mobile notification from a message limited to K characters; if too long, remove whole words from the end.
• If cropped, append a space and "..." and keep length no more than K; if nothing fits, return "...".
• Inputs/outputs: String message and int K; output the final notification string.
• Constraints: K [3..500], message length [1..500], letters and single spaces, no leading/trailing spaces.
• Microsoft interviews coding interview problem in a mobile UX context; a common interview question.