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