mirror of
https://github.com/emirpasic/gods
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114 lines
2.9 KiB
Go
114 lines
2.9 KiB
Go
// Copyright (c) 2015, Emir Pasic. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package examples
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import (
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"fmt"
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rbt "github.com/emirpasic/gods/trees/redblacktree"
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)
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// RedBlackTreeExtended to demonstrate how to extend a RedBlackTree to include new functions
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type RedBlackTreeExtended struct {
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*rbt.Tree
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}
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// GetMin gets the min value and flag if found
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func (tree *RedBlackTreeExtended) GetMin() (value interface{}, found bool) {
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node, found := tree.getMinFromNode(tree.Root)
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if node != nil {
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return node.Value, found
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}
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return nil, false
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}
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// GetMax gets the max value and flag if found
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func (tree *RedBlackTreeExtended) GetMax() (value interface{}, found bool) {
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node, found := tree.getMaxFromNode(tree.Root)
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if node != nil {
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return node.Value, found
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}
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return nil, false
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}
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// RemoveMin removes the min value and flag if found
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func (tree *RedBlackTreeExtended) RemoveMin() (value interface{}, deleted bool) {
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node, found := tree.getMinFromNode(tree.Root)
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if found {
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tree.Remove(node.Key)
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return node.Value, found
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}
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return nil, false
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}
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// RemoveMax removes the max value and flag if found
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func (tree *RedBlackTreeExtended) RemoveMax() (value interface{}, deleted bool) {
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node, found := tree.getMaxFromNode(tree.Root)
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if found {
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tree.Remove(node.Key)
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return node.Value, found
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}
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return nil, false
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}
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func (tree *RedBlackTreeExtended) getMinFromNode(node *rbt.Node) (foundNode *rbt.Node, found bool) {
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if node == nil {
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return nil, false
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}
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if node.Left == nil {
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return node, true
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}
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return tree.getMinFromNode(node.Left)
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}
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func (tree *RedBlackTreeExtended) getMaxFromNode(node *rbt.Node) (foundNode *rbt.Node, found bool) {
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if node == nil {
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return nil, false
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}
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if node.Right == nil {
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return node, true
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}
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return tree.getMaxFromNode(node.Right)
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}
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func print(tree *RedBlackTreeExtended) {
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max, _ := tree.GetMax()
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min, _ := tree.GetMin()
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fmt.Printf("Value for max key: %v \n", max)
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fmt.Printf("Value for min key: %v \n", min)
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fmt.Println(tree)
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}
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// RedBlackTreeExtendedExample main method on how to use the custom red-black tree above
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func RedBlackTreeExtendedExample() {
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tree := RedBlackTreeExtended{rbt.NewWithIntComparator()}
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tree.Put(1, "a") // 1->x (in order)
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tree.Put(2, "b") // 1->x, 2->b (in order)
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tree.Put(3, "c") // 1->x, 2->b, 3->c (in order)
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tree.Put(4, "d") // 1->x, 2->b, 3->c, 4->d (in order)
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tree.Put(5, "e") // 1->x, 2->b, 3->c, 4->d, 5->e (in order)
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print(&tree)
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// Value for max key: e
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// Value for min key: a
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// RedBlackTree
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// │ ┌── 5
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// │ ┌── 4
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// │ │ └── 3
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// └── 2
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// └── 1
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tree.RemoveMin() // 2->b, 3->c, 4->d, 5->e (in order)
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tree.RemoveMax() // 2->b, 3->c, 4->d (in order)
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tree.RemoveMin() // 3->c, 4->d (in order)
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tree.RemoveMax() // 3->c (in order)
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print(&tree)
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// Value for max key: c
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// Value for min key: c
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// RedBlackTree
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// └── 3
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}
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