Backtracking Checkpoint

1. When saving a path to results in backtracking, you must:

Make a copy of the path Return the path directly Clear the path Reverse the path

2. Subsets uses a 'start' index to:

Avoid duplicates like [2,1] when [1,2] exists Track visited elements Count subsets Sort elements

3. How many subsets does an array of n elements have?

4. In N-Queens, cells on the same diagonal have equal:

row - col or row + col row * col row only col only

5. How many permutations does an array of n distinct elements have?