Agreed, I just lost because of improper python syntax. Hardcore C would be more fun, with memsets and frees such that bugs can exist in memory management.

Yeah. I'm no Python programmer, so I screwed up one of the practices by writing `set.push(node)` instead of `set.add(node)`. Luckily that didn't matter on the challenge itself (except for the wasted seconds checking all my assumptions about what the python functions were doing).