That's because the array to be sorted is packed and inflated, so as to be the worst possible input for that kind of sort. Worst-case complexity. Also, I neede

That's because the array to be sorted is packed and inflated, so as to be the worst possible input for that kind of sort. Worst-case complexity. Also, I needed to bump my JVM heap up to 16GB (not 9GB as recommended), just to run it.