C++ STL-style skiplist
I wrote this to find out if a skiplist was faster than the STL map, slightly under a decade ago.
At the time, I recall it was - the current std::map in GCC appears to be marginally faster. I suspect that C++14 improvements would let me add a bit of speed to this - whether that'd be enough to get it into the lead I don't know.
The tests don't do much iteration, because they're really benchmarks, and a skiplist ought to be zillions of times faster than a red-black tree at traversal.