37 lines
726 B
Go
37 lines
726 B
Go
package sorting
|
|
|
|
type shell struct{}
|
|
|
|
func (*shell) Sort(items Sortable) {
|
|
len := items.Len()
|
|
gap := 1
|
|
|
|
// Calculating gap maximum value.
|
|
// This is for "Sedgewick gap sequence" variation.
|
|
// Another sequences can be used
|
|
for gap < len/3 {
|
|
gap = gap*3 + 1
|
|
}
|
|
|
|
// This loop needed to progressively degrease gap until siple insertion
|
|
// sort will be used
|
|
for gap >= 1 {
|
|
|
|
// Insertion sort loop
|
|
for i := gap; i < len; i++ {
|
|
|
|
// Instead of comparing adjacent elements we compare
|
|
// gap distance elements and swap them
|
|
for j := i; j >= gap && items.Less(j, j-gap); j -= gap {
|
|
items.Swap(j, j-gap)
|
|
}
|
|
}
|
|
|
|
// "Sedgewick gap sequence"
|
|
gap = gap / 3
|
|
}
|
|
}
|
|
|
|
func NewShell() Sorter {
|
|
return &shell{}
|
|
}
|