[swift][06_linkedlist][add]

[swift][07_linkedlist][add]
[swift][08_stack][add]

swift/06_linkedlist/SinglyLinkedList.swift

@@ -0,0 +1,128 @@
+//
+//  Created by Jiandan on 2018/10/12.
+//  Copyright © 2018 Jiandan. All rights reserved.
+//
+
+import Foundation
+
+class Node<T> {
+    var value: T?
+    var next: Node?
+
+    init(){}
+
+    init(value: T) {
+        self.value = value
+    }
+}
+
+/// 单链表
+/// 实现插入、删除、查找操作
+class List<Element: Equatable> {
+    private var dummy = Node<Element>() // 哨兵结点，不存储数据
+    var size: Int {
+        var num = 0
+        var tmpNode = dummy.next
+        while tmpNode != nil {
+            num += 1
+            tmpNode = tmpNode!.next
+        }
+        return num
+    }
+    var isEmpty: Bool { return size > 0 }
+
+    /// find node with value
+    func node(with value: Element) -> Node<Element>? {
+        var node = dummy.next
+        while node != nil {
+            if node!.value == value {
+                return node
+            }
+            node = node!.next
+        }
+
+        return nil
+    }
+    // 约定：链表的 index 从 1 开始
+    func node(at index: Int) -> Node<Element>? {
+        var num = 1
+        var node = dummy.next
+        while node != nil {
+            if num == index {
+                return node
+            }
+            node = node!.next
+            num += 1
+        }
+        return nil
+    }
+
+    func insertToHead(value: Element) {
+        let newNode = Node(value: value)
+        return insertToHead(node: newNode)
+    }
+
+    func insertToHead(node: Node<Element>) {
+        node.next = dummy.next
+        dummy.next = node
+    }
+
+    func insert(after node: Node<Element>, newValue: Element) {
+        let newNode = Node(value: newValue)
+        return insert(after: node, newNode: newNode)
+    }
+
+    func insert(after node: Node<Element>, newNode: Node<Element>) {
+        newNode.next = node.next
+        node.next = newNode
+    }
+
+    func insert(before node: Node<Element>, newValue: Element) {
+        let newNode = Node(value: newValue)
+        return insert(before: node, newNode: newNode)
+    }
+
+    func insert(before node: Node<Element>, newNode: Node<Element>) {
+        var lastNode = dummy
+        var tmpNode = dummy.next
+
+        while tmpNode != nil {
+            if tmpNode === node {
+                newNode.next = tmpNode
+                lastNode.next = newNode
+                break
+            }
+            lastNode = tmpNode!
+            tmpNode = tmpNode!.next
+        }
+    }
+
+    func delete(node: Node<Element>) {
+        var lastNode = dummy
+        var tmpNode = dummy.next
+
+        while tmpNode != nil {
+            if tmpNode === node {
+                lastNode.next = tmpNode!.next
+                break
+            }
+
+            lastNode = tmpNode!
+            tmpNode = tmpNode!.next
+        }
+    }
+    /// 删除首个 value 符合要求的结点
+    func delete(value: Element) {
+        var lastNode = dummy
+        var tmpNode = dummy.next
+        while tmpNode != nil {
+            if tmpNode!.value == value {
+                lastNode.next = tmpNode!.next
+                break
+            }
+
+            lastNode = tmpNode!
+            tmpNode = tmpNode!.next
+        }
+    }
+}

swift/07_linkedlist/LinkedListAlgo.swift

@@ -0,0 +1,111 @@
+//
+// Created by Jiandan on 2018/10/13.
+// Copyright (c) 2018 Jiandan. All rights reserved.
+//
+
+/**
+ * 1) 单链表反转
+ * 2) 链表中环的检测
+ * 3) 两个有序的链表合并
+ * 4) 删除链表倒数第n个结点
+ * 5) 求链表的中间结点
+ */
+import Foundation
+/// 单链表反转
+func reverseSinglyLinkedList<Element>(head: Node<Element>) -> Node<Element>? {
+    var reverseHead: Node<Element>?, currentNode: Node<Element>?, prevNode: Node<Element>?
+    currentNode = head
+    while currentNode != nil {
+        let nextNode = currentNode!.next
+        if nextNode == nil {
+            reverseHead = currentNode
+        }
+        currentNode!.next = prevNode
+        prevNode = currentNode
+        currentNode = nextNode
+    }
+    return reverseHead
+}
+/// 检测环
+func hasCircle<Element>(head: Node<Element>) -> Bool {
+    var fast = head.next
+    var slow: Node<Element>? = head
+    while fast != nil {
+        if fast === slow {
+            return true
+        }
+        fast = fast!.next?.next
+        slow = slow!.next
+    }
+    return false
+}
+/// 两个有序的链表合并
+func mergeSortedLists<Element: Comparable>(headA: Node<Element>?, headB: Node<Element>?) -> Node<Element>? {
+    guard let headA = headA else {
+        return headB
+    }
+    guard let headB = headB else {
+        return headA
+    }
+
+    var head: Node<Element>?, tail: Node<Element>?
+    var nodeA: Node<Element>? = headA, nodeB: Node<Element>? = headB
+    if nodeA!.value! < nodeB!.value! {
+        head = nodeA
+        nodeA = nodeA!.next
+    } else {
+        head = nodeB
+        nodeB = nodeB!.next
+    }
+    tail = head
+
+    while nodeA != nil, nodeB != nil {
+        if nodeA!.value! < nodeB!.value! {
+            tail!.next = nodeA
+            nodeA = nodeA!.next
+        } else {
+            tail!.next = nodeB
+            nodeB = nodeB!.next
+        }
+        tail = tail!.next
+    }
+
+    if nodeA != nil {
+        tail?.next = nodeA
+    } else {
+        tail?.next = nodeB
+    }
+
+    return head
+}
+
+/// 删除倒数第n个结点
+func deleteNode<Element>(at lastNum: Int, in head: Node<Element>) {
+    var slow: Node<Element>? = head
+    var fast: Node<Element>? = head
+    var num = 1
+    while fast != nil, num < lastNum {
+        fast = fast!.next
+        num += 1
+    }
+
+    var prevNode: Node<Element>?
+    while fast != nil {
+        prevNode = slow
+        fast = fast!.next
+        slow = slow!.next
+    }
+    prevNode?.next = slow?.next
+}
+
+/// 求链表的中间结点
+func halfNode<Element>(in head: Node<Element>) -> Node<Element>? {
+    var slow: Node<Element>? = head
+    var fast: Node<Element>? = head
+
+    while fast?.next != nil, fast?.next?.next != nil {
+        fast = fast!.next?.next
+        slow = slow!.next
+    }
+    return slow
+}

swift/08_stack/Browser.swift

@@ -0,0 +1,27 @@
+//
+// Created by Jiandan on 2018/10/12.
+// Copyright (c) 2018 Jiandan. All rights reserved.
+//
+
+import Foundation
+
+struct Page {
+    /// 存储前进 url
+    private var forwardArray = [String]()
+    /// 存储后退 url
+    private var backArray = [String]()
+
+    var currentURL: String? { return forwardArray.last }
+
+    init(url: String) {
+        forwardArray.append(url)
+    }
+    /// 前进
+    mutating func goForward(url: String) {
+        forwardArray.append(url)
+    }
+    /// 后退
+    mutating func goBack() {
+        backArray.append(forwardArray.popLast()!)
+    }
+}