I'll start by echoing thenewwazoo's comment - I learnt Ruby on these challenges, and I would actually suggest the questions are better worded, more generally ed

I'll start by echoing thenewwazoo's comment - I learnt Ruby on these challenges, and I would actually suggest the questions are better worded, more generally educational and generally laid out than most of Hacker Rank. For example, you're forced to write maintainable code, because your solution to one question ends up adapted to a later question. I hit two different Ruby segfault conditions someone patched just so I could finish this challenge. You know you're deep in a language when that happens. For anyone who finished Set 8: give yourself an exceptional pat on the back. I'm looking forward to revisiting this at a time when it hopefully goes more public. Downsides: Extreme jadedness towards commercial encryption products and the people that peddle them.