Implement a multi-button click detector

Implement a click detector for multiple physical buttons.

You receive button state updates as a stream. Each update provides:

• button_id (integer)
• state where 1 = pressed, 0 = released
• (initially) updates arrive every 10 ms per button (you may assume updates are ordered in time).

A “click” is a press followed by a release. Classify each completed click as:

• Single Click: press duration ≤ 200 ms
• Long Click: press duration ≥ 500 ms

For each detected click, output something like:

• Button 1: Single Click
• Button 2: Long Click

Requirements / edge cases:

• Support multiple buttons concurrently.
• Handle back-to-back clicks on the same button (press/release cycles repeated over time).
• Handle no click (e.g., no transitions) without producing output.
• Clarify/handle what to do for press durations in the (200 ms, 500 ms) gap.

Follow-up: If state updates do not arrive every 10 ms (variable intervals), how would you modify the implementation? Assume you can obtain timestamps (e.g., via a system call like now_ms()) for each update.