LinkedList #21 (#24)

homeworks/sergii.suprun_differz/homework_2/LinkedList.playground/Contents.swift

@@ -0,0 +1,250 @@
+import UIKit
+
+protocol LinkedList: class, Sequence, CustomStringConvertible {
+    associatedtype T
+    var count: Int { get }
+    var isEmpty: Bool { get }
+    func add(value: T)
+    func remove(value: T) -> Bool
+    func remove(index: Int) throws -> Bool
+}
+
+enum LinkedListError: Error {
+    case indexOutOfBounds
+}
+
+extension LinkedList {
+    public var description: String {
+        var text = ""
+        for node in self {
+            if !text.isEmpty {
+                text += ", "
+            }
+            text += "\(node)"
+        }
+        return "[\(text)]"
+    }
+}
+
+extension LinkedList where T == Self.Element {
+    func append(contentsOf elements: Self) {
+        for e in elements {
+            self.add(value: e)
+        }
+    }
+}
+
+public struct LinkedListIterator<T: Equatable>: IteratorProtocol {
+    private var current: Node<T>?
+
+    init(head: Node<T>?) {
+        current = head
+    }
+    public mutating func next() -> T? {
+        guard let this = current else {
+            return nil
+        }
+        current = this.next
+        return this.value
+    }
+}
+
+public class Node<T: Equatable>: CustomStringConvertible {
+    let value: T
+    var next: Node<T>?
+    var prev: Node<T>?
+
+    init(value: T) {
+        self.value = value
+    }
+    public var description: String {
+        return "node:\(value)"
+    }
+}
+
+public class SinglyLinkedList<T: Equatable>: LinkedList {
+    private var head: Node<T>?
+    private var tail: Node<T>?
+    private var size: Int = 0
+
+    public func add(value: T) {
+        let node = Node(value: value)
+        if isEmpty {
+            head = node
+        } else {
+            tail?.next = node
+        }
+        tail = node
+        size += 1
+    }
+    public func remove(value: T) -> Bool {
+        var prev: Node<T>?
+        var node = head
+        while node != nil {
+            if node!.value == value {
+                size -= 1
+                unlink(prev: prev, node: node)
+                return true
+            }
+            prev = node
+            node = node?.next
+        }
+        return false
+    }
+    public func remove(index: Int) throws -> Bool {
+        if index < 0 || index >= size {
+            throw LinkedListError.indexOutOfBounds
+        }
+        var prev: Node<T>?
+        var node = head
+        var i = 0
+        while node != nil && i < size {
+            if i == index {
+                size -= 1
+                unlink(prev: prev, node: node)
+                return true
+            }
+            prev = node
+            node = node?.next
+            i += 1
+        }
+        return false
+    }
+    private func unlink(prev: Node<T>?, node: Node<T>?) {
+        let next = node?.next
+        if prev == nil {
+            head = next
+        } else {
+            prev?.next = next
+        }
+    }
+    public var isEmpty: Bool {
+        return head == nil
+    }
+    public var count: Int {
+        return size
+    }
+    public func makeIterator() -> LinkedListIterator<T> {
+        return LinkedListIterator<T>(head: head)
+    }
+}
+
+
+var list = SinglyLinkedList<String>()
+list.add(value: "A")
+list.add(value: "B")
+list.add(value: "C")
+list.add(value: "D")
+list.remove(value: "B")
+do {
+    try list.remove(index: 1)
+    try list.remove(index: 99)
+} catch {
+    print("Unexpected error: \(error).")
+}
+
+print(list)
+for element in list {
+    print(element)
+}
+
+
+public class DoublyLinkedList<T: Equatable>: LinkedList {
+    private var head: Node<T>?
+    private var tail: Node<T>?
+    private var size: Int = 0
+
+    public func add(value: T) {
+        let node = Node(value: value)
+        if isEmpty {
+            head = node
+        } else {
+            tail?.next = node
+            node.prev = tail
+        }
+        tail = node
+        size += 1
+    }
+    public func remove(value: T) -> Bool {
+        var prev: Node<T>?
+        var node = head
+        while node != nil {
+            if node!.value == value {
+                size -= 1
+                unlink(prev: prev, node: node)
+                return true
+            }
+            prev = node
+            node = node?.next
+        }
+        return false
+    }
+    public func remove(index: Int) throws -> Bool {
+        if index < 0 || index >= size {
+            throw LinkedListError.indexOutOfBounds
+        }
+        var prev: Node<T>?
+        var node = head
+        var i = 0
+        while node != nil && i < size {
+            if i == index {
+                size -= 1
+                unlink(prev: prev, node: node)
+                return true
+            }
+            prev = node
+            node = node?.next
+            i += 1
+        }
+        return false
+    }
+    private func unlink(prev: Node<T>?, node: Node<T>?) {
+        let next = node?.next
+        if prev == nil {
+            head = next
+        } else {
+            prev?.next = next
+        }
+        if next != nil {
+            next?.prev = prev
+        }
+    }
+    public var isEmpty: Bool {
+        return head == nil
+    }
+    public var count: Int {
+        return size
+    }
+    public func makeIterator() -> LinkedListIterator<T> {
+        return LinkedListIterator<T>(head: head)
+    }
+    public func reverse() -> DoublyLinkedList {
+        var node = head
+        while let current = node {
+            node = current.next
+            swap(&current.next, &current.prev)
+            head = current
+        }
+        return self
+    }
+}
+
+let list2 = DoublyLinkedList<String>()
+list2.add(value: "A")
+list2.add(value: "B")
+list2.add(value: "C")
+list2.add(value: "D")
+print(list2)
+list2.reverse()
+print(list2)
+for element in list2.reversed() {
+    print(element)
+}
+
+print("--------")
+var list3 = SinglyLinkedList<String>()
+list3.add(value: "1")
+list3.add(value: "2")
+list3.add(value: "3")
+list.append(contentsOf: list3)
+print(list)

homeworks/sergii.suprun_differz/homework_2/LinkedList.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' executeOnSourceChanges='false'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

homeworks/sergii.suprun_differz/homework_2/LinkedList.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>