Your solution is not naive in my opinion because you set the size of the buffer and use map/filter but ok... Let's check. Your solution is the slowest from all the solutions.
It took 4.6s which only confirms what I wrote on beginning when we started this discussion. Perf counters for your solution in here:
It took 4.6s which only confirms what I wrote on beginning when we started this discussion. Perf counters for your solution in here:
http://pastebin.com/Anak1ahe