> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/s/sorting-algorithms/cycle_sort.md).

# Cycle sort

```ruby
func cycle_sort (array) {
    var (writes=0, pos=0)
 
    func f(i, Ref item, bool=false) {
        pos = (i + array.slice(i+1).count{ _ < *item })
        return(false) if (bool && pos==i)
        while (*item == array[pos]) { ++pos }
        (array[pos], *item) = (*item, array[pos])
        ++writes
        return true
    }
 
    array.each_kv { |i, item|
        f(i, \item, true) || next
        while (pos != i) {
            f(i, \item)
        }
    }
 
    return writes
}
 
var a = %n(0 1 2 2 2 2 1 9 3.5 5 8 4 7 0 6)
 
say a.join(' ')
say ('writes ', cycle_sort(a))
say a.join(' ')
```

#### Output:

```
0 1 2 2 2 2 1 9 3.5 5 8 4 7 0 6
writes 10
0 0 1 1 2 2 2 2 3.5 4 5 6 7 8 9
```