#30Smart Traffic Signal Sequence

A smart traffic controller needs to cycle through 2^n unique signal states. Each state is represented using n binary switches. To ensure smooth transitions, exactly one switch must change between every two consecutive states. The transition from the final state back to the first must also change exactly one switch.

Given an integer n, return any valid sequence of all 2^n signal states satisfying these conditions.

Real-World Applications: Error-resistant data transmission; Karnaugh maps and digital circuit design; Analog-to-digital converters;