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

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: http://pastebin.com/Anak1ahe http://pastebin.com/Anak1ahe