If you already implemented the solution to the problem, answer the following questions:

1. How does your implementation compare to the one below?
2. Is your implementation better than this one?
3. What is the time complexity (for now we can say the big-O notation)?
 

If you have not implemented yet, do the following:

1. Trace the code for 4 queens. It only has 2 solutions but 1 unique.
2. Explain how the implementation works
3. What is the time complexity (for now we can say the big-O notation)?