Function cycle_sort 

pub fn cycle_sort<T>(slice: &mut [T]) -> usize
where
    T: Ord,

Sorts a slice using the elements’ natural ordering and returns the number of writes made.

Examples

let mut a = [1, 4, 1, 5, 9, 2];
let     w = cycle_sort(&mut a);

assert_eq!(a, [1, 1, 2, 4, 5, 9]);
assert_eq!(w, 5);