Permutation Sort Algorithm Very Slow

[Chris Cain via Digitalmars-d-learn]

On Saturday, 7 June 2014 at 21:40:08 UTC, Agora wrote:
> Why is running slow?

One of the main reasons is because the number of permutations an 
array has is n!. Thus the expected runtime is O(n!). That's a 
slow, slow algorithm in general. In particular, your array with 
length 11 has 39,916,800 permutations (although it, obviously, 
doesn't have to go through *all* of those to get the sorted 
sequence in this case).