mirror of
https://github.com/emirpasic/gods
synced 2024-11-06 15:20:25 +00:00
220 lines
6.1 KiB
Go
220 lines
6.1 KiB
Go
/*
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Copyright (c) 2015, Emir Pasic
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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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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type RedBlackTreeExtended struct {
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*rbt.Tree
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}
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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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} else {
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return nil, false
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}
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}
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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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} else {
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return nil, false
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}
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}
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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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} else {
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return nil, false
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}
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}
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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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} else {
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return nil, false
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}
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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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} else {
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return tree.getMinFromNode(node.Left)
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}
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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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} else {
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return tree.getMaxFromNode(node.Right)
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}
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}
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// Find ceiling node of the input key, return the ceiling node or nil if no ceiling is found.
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// Second return parameter is true if ceiling was found, otherwise false.
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//
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// Ceiling node is defined as the smallest node that is larger than or equal to the given node.
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// A ceiling node may not be found, either because the tree is empty, or because
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// all nodes in the tree is smaller than the given node.
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//
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// Key should adhere to the comparator's type assertion, otherwise method panics.
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func (tree *RedBlackTreeExtended) Ceiling(key interface{}) (ceiling *rbt.Node, found bool) {
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found = false
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node := tree.Root
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for node != nil {
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compare := tree.Comparator(key, node.Key)
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switch {
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case compare == 0:
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return node, true
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case compare < 0:
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ceiling, found = node, true
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node = node.Left
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case compare > 0:
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node = node.Right
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}
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}
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if found {
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return ceiling, true
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}
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return nil, false
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}
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// Find floor node of the input key, return the floor node or nil if no ceiling is found.
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// Second return parameter is true if floor was found, otherwise false.
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//
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// Floor node is defined as the largest node that is smaller than or equal to the given node.
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// A floor node may not be found, either because the tree is empty, or because
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// all nodes in the tree is larger than the given node.
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//
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// Key should adhere to the comparator's type assertion, otherwise method panics.
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func (tree *RedBlackTreeExtended) Floor(key interface{}) (floor *rbt.Node, found bool) {
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found = false
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node := tree.Root
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for node != nil {
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compare := tree.Comparator(key, node.Key)
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switch {
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case compare == 0:
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return node, true
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case compare < 0:
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node = node.Left
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case compare > 0:
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floor, found = node, true
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node = node.Right
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}
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}
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if found {
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return floor, true
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}
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return nil, false
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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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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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// Ceiling and Floor functions
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tree = RedBlackTreeExtended{rbt.NewWithIntComparator()}
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tree.Put(1, "a")
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tree.Put(2, "b")
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tree.Put(4, "d")
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tree.Put(6, "f")
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tree.Put(7, "g")
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//index, ceiling, floor
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testValues := [][]interface{}{
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{0, 1, nil},
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{1, 1, 1},
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{2, 2, 2},
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{3, 4, 2},
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{4, 4, 4},
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{5, 6, 4},
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{6, 6, 6},
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{7, 7, 7},
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{8, nil, 7},
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}
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for _, tt := range testValues {
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actualCeiling, _ := tree.Ceiling(tt[0])
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actualFloor, _ := tree.Floor(tt[0])
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fmt.Printf("test key %d, expected (%d, %d), actual (%d, %d)\n", tt[0], tt[1], tt[2], actualCeiling.Key, actualFloor.Key)
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}
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}
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