129 lines
3.1 KiB
Swift
129 lines
3.1 KiB
Swift
//
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// Created by Jiandan on 2018/10/12.
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// Copyright © 2018 Jiandan. All rights reserved.
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//
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import Foundation
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class Node<T> {
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var value: T?
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var next: Node?
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init(){}
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init(value: T) {
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self.value = value
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}
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}
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/// 单链表
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/// 实现插入、删除、查找操作
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class List<Element: Equatable> {
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private var dummy = Node<Element>() // 哨兵结点，不存储数据
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var size: Int {
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var num = 0
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var tmpNode = dummy.next
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while tmpNode != nil {
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num += 1
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tmpNode = tmpNode!.next
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}
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return num
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}
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var isEmpty: Bool { return size > 0 }
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/// find node with value
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func node(with value: Element) -> Node<Element>? {
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var node = dummy.next
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while node != nil {
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if node!.value == value {
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return node
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}
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node = node!.next
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}
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return nil
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}
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// 约定：链表的 index 从 1 开始
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func node(at index: Int) -> Node<Element>? {
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var num = 1
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var node = dummy.next
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while node != nil {
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if num == index {
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return node
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}
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node = node!.next
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num += 1
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}
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return nil
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}
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func insertToHead(value: Element) {
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let newNode = Node(value: value)
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return insertToHead(node: newNode)
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}
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func insertToHead(node: Node<Element>) {
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node.next = dummy.next
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dummy.next = node
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}
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func insert(after node: Node<Element>, newValue: Element) {
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let newNode = Node(value: newValue)
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return insert(after: node, newNode: newNode)
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}
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func insert(after node: Node<Element>, newNode: Node<Element>) {
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newNode.next = node.next
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node.next = newNode
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}
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func insert(before node: Node<Element>, newValue: Element) {
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let newNode = Node(value: newValue)
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return insert(before: node, newNode: newNode)
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}
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func insert(before node: Node<Element>, newNode: Node<Element>) {
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var lastNode = dummy
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var tmpNode = dummy.next
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while tmpNode != nil {
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if tmpNode === node {
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newNode.next = tmpNode
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lastNode.next = newNode
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break
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}
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lastNode = tmpNode!
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tmpNode = tmpNode!.next
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}
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}
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func delete(node: Node<Element>) {
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var lastNode = dummy
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var tmpNode = dummy.next
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while tmpNode != nil {
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if tmpNode === node {
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lastNode.next = tmpNode!.next
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break
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}
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lastNode = tmpNode!
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tmpNode = tmpNode!.next
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}
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}
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/// 删除首个 value 符合要求的结点
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func delete(value: Element) {
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var lastNode = dummy
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var tmpNode = dummy.next
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while tmpNode != nil {
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if tmpNode!.value == value {
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lastNode.next = tmpNode!.next
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break
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}
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lastNode = tmpNode!
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tmpNode = tmpNode!.next
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}
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}
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}
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