mirror of
https://github.com/wbbaddons/Tims-Chat.git
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127 lines
2.4 KiB
JavaScript
127 lines
2.4 KiB
JavaScript
/*
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* Copyright (c) 2010-2021 Tim Düsterhus.
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*
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* Use of this software is governed by the Business Source License
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* included in the LICENSE file.
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*
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* Change Date: 2027-02-22
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*
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* On the date above, in accordance with the Business Source
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* License, use of this software will be governed by version 2
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* or later of the General Public License.
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*/
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define(['./Node'], function (Node) {
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'use strict'
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class Tree {
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constructor() {
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this.root = undefined
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}
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search(value) {
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if (this.root !== undefined) return this.root.search(value)
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return undefined
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}
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insert(value) {
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const node = new Node(value)
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if (this.root === undefined) {
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this.root = node
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this.fix(node)
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return ['RIGHT', undefined]
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}
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const search = this.search(value)
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const [side, parent] = search
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if (side === 'IS') return [side, parent.value]
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if (side === 'LEFT') {
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parent.left = node
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this.fix(node)
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return [side, parent.value]
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}
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if (side === 'RIGHT') {
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parent.right = node
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this.fix(node)
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return [side, parent.value]
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}
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throw new Error('Unreachable')
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}
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fix(N) {
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// Case 1:
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if (N.parent === undefined) {
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N.color = 'BLACK'
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return
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}
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// Case 2:
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if (N.parent.color === 'BLACK') {
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return
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}
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// Case 3:
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const U = N.uncle
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if (U !== undefined && U.color === 'RED') {
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N.parent.color = 'BLACK'
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U.color = 'BLACK'
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const G = N.grandparent
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G.color = 'RED'
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this.fix(G)
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return
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}
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// Case 4:
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if (N.isRightChild && N.parent.isLeftChild) {
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this.rotateLeft(N.parent)
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N = N.left
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} else if (N.isLeftChild && N.parent.isRightChild) {
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this.rotateRight(N.parent)
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N = N.right
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}
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// Case 5
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const G = N.grandparent
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N.parent.color = 'BLACK'
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G.color = 'RED'
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if (N.isLeftChild) {
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this.rotateRight(G)
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} else {
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this.rotateLeft(G)
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}
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}
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rotateLeft(N) {
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if (N.right === undefined) return
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const right = N.right
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N.right = right.left
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if (N.parent === undefined) {
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this.root = right
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} else if (N.isLeftChild) {
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N.parent.left = right
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} else if (N.isRightChild) {
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N.parent.right = right
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}
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right.left = N
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}
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rotateRight(N) {
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if (N.left === undefined) return
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const left = N.left
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N.left = left.right
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if (N.parent === undefined) {
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this.root = left
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} else if (N.isLeftChild) {
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N.parent.left = left
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} else if (N.isRightChild) {
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N.parent.right = left
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}
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left.right = N
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}
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}
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return Tree
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})
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