Related: Morris Traversal (no parent link required). https://en.wikipedia.org/wiki/Tree_traversal#Morris_in-order_traversal_using_threading https://en.wikipedi

Related: Morris Traversal (no parent link required). https://en.wikipedia.org/wiki/Tree_traversal#Morris_in-order_traversal_using_threading https://en.wikipedia.org/wiki/Tree_traversal#Morris_in-order... Trying to reimplement it without looking at the solution is fun.