Simple Cycle sort implementation.

Cycle sort is an unstable comparison sort that minimizes the number of writes. It has a best- and worst-case performance of O(n^2), making it slow on large sets of data. It is useful when writes are expensive and want to be reduced.

Because the algorithm performs in O(n^2) for sorted lists, you may want to consider checking if sorting is necessary before actually sorting.

Panics

If the comparison function passed to cycle_sort_by or the key extraction function passed to cycle_sort_by_key panics, the data being sorted is likely to end up in an invalid state.