51 lines
1023 B
Go
51 lines
1023 B
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
|
|
// See page 101.
|
|
|
|
// Package treesort provides insertion sort using an unbalanced binary tree.
|
|
package treesort
|
|
|
|
//!+
|
|
type tree struct {
|
|
value int
|
|
left, right *tree
|
|
}
|
|
|
|
// Sort sorts values in place.
|
|
func Sort(values []int) {
|
|
var root *tree
|
|
for _, v := range values {
|
|
root = add(root, v)
|
|
}
|
|
appendValues(values[:0], root)
|
|
}
|
|
|
|
// appendValues appends the elements of t to values in order
|
|
// and returns the resulting slice.
|
|
func appendValues(values []int, t *tree) []int {
|
|
if t != nil {
|
|
values = appendValues(values, t.left)
|
|
values = append(values, t.value)
|
|
values = appendValues(values, t.right)
|
|
}
|
|
return values
|
|
}
|
|
|
|
func add(t *tree, value int) *tree {
|
|
if t == nil {
|
|
// Equivalent to return &tree{value: value}.
|
|
t = new(tree)
|
|
t.value = value
|
|
return t
|
|
}
|
|
if value < t.value {
|
|
t.left = add(t.left, value)
|
|
} else {
|
|
t.right = add(t.right, value)
|
|
}
|
|
return t
|
|
}
|
|
|
|
//!-
|