Oh! I think I know: My comparator returns a difference, which is fine for `qsort`. But I'll bet `algorithm.sort` expects strictly `[-1, 0, 1]`.
I'll try with that and post later...
Oh! I think I know: My comparator returns a difference, which is fine for `qsort`. But I'll bet `algorithm.sort` expects strictly `[-1, 0, 1]`.
I'll try with that and post later...