You `Node` is basically same as `SinglyLinkedNode[int]`, so your question is `Can I insert or remove in arbitrary spots with rings?` The answer is unfortunately no...
I started part 1 with SinglyLinkedRing and then I found that the my program hang. Originally I thought I did something wrong in the while loop, but later I found that it is actually the `echo` on ring cause the indefinite hang... because I created new nodes instead of reusing existing ones. This costs me some time to debug... For part 2, I just start with nodes only, no rings, reuse the same nodes and use a `Table[int, SinglyLinkedNode]` for lookup (an array maybe better actually). [My solution](https://github.com/jackhftang/adventofcode2020/blob/main/day23/day23_2.nim) is only one main proc. This is the same code as my final submission to AOC 1331/447.
