Array.swift

//
// Array.swift
// Array
//
// Created by ggl on 2019/3/20.
// Copyright © 2019年 ggl. All rights reserved.
// 大小固定的有序动态扩容数组

import Foundation

class DynamicExpansionArray {
 /// 数组底层存储结构
 var array: UnsafeMutablePointer<Int>
 
 /// 数组元素个数
 var size: Int
 
 /// 数组容量大小
 var capcity: Int
 
 /// 初始化方法
 ///
 /// - Parameter capcity: 数组容量大小
 init(capcity: Int) {
 size = 0
 self.capcity = capcity
 array = UnsafeMutablePointer<Int>.allocate(capacity: capcity)
 array.initialize(repeating: Int.min, count: capcity)
 }
 
 /// 增加元素
 ///
 /// - Parameter num: 要增加的数字
 func add(num: Int) {
 if size >= capcity {
 let tempArray = array
 array = UnsafeMutablePointer<Int>.allocate(capacity: capcity * 2)
 array.initialize(repeating: Int.min, count: capcity * 2)
 array.assign(from: tempArray, count: size)
 tempArray.deallocate()
 capcity *= 2
 }
 array[size] = num
 size += 1
 }
 
 /// 插入元素
 ///
 /// - Parameters:
 /// - num: 要增加的数字
 /// - at: 位置下标
 /// - Returns: 插入是否成功
 @discardableResult
 func insert(num: Int, at index: Int) -> Bool {
 if index < 0 {
 Swift.print("下标位置错误")
 return false
 }
 
 add(num: num)
 if index < size - 1 {
 //交换位置
 let pNum = array[index]
 array[index] = num
 array[size-1] = pNum
 }
 return true
 }
 
 /// 删除元素
 ///
 /// - Parameter at: 位置下标
 /// - Returns: 是否成功
 @discardableResult
 func remove(at index: Int) -> Bool {
 if index < 0 || index >= size {
 return false
 }
 for i in index..<size-1 {
 array[i] = array[i+1]
 }
 size -= 1
 return true
 }
 
 /// 打印元素
 func print() {
 Swift.print("[", terminator: "")
 for i in 0..<size {
 if i == size - 1 {
 Swift.print(array[size-1], terminator: "]")
 } else {
 Swift.print(array[i], terminator: " ")
 }
 }
 Swift.print("")
 }
 
 deinit {
 array.deinitialize(count: capcity)
 array.deallocate()
 }
}