基于数组来实现的顺序栈和基于链表来实现的链式栈

# Stack 基于数组来实现的顺序栈和基于链表来实现的链式栈 ## 顺序栈 1.1 实现 ```objectivec //MARK: - 顺序栈 class ArrayStack: NSObject { var stack: Array<Any>? //栈的大小 var size: Int? //栈中元素个数 var count: Int? /// 初始化栈 /// - Parameter size: 栈的大小 init(size: Int) { self.count = 0 self.size = size self.stack = Array.init() } } ``` 1.2 进栈 ```objectivec /// 进栈 /// - Parameter data: 进栈数据 /// - Returns: 进栈结果 func push(data: Any) -> Bool { if count == size { //栈满了 return false } if stack!.count > count! { stack![count!] = data }else { stack?.append(data) } count! += 1 return true } ``` 1.3出栈 ```objectivec /// 出栈 /// - Returns: 出栈数据 func pop() -> Any? { if count == 0 { //栈里面没数据 return nil } let data = stack![count! - 1] count! -= 1 return data } ``` ## 链式栈 1.1实现 ```objectivec class ListStack: NSObject { /// 单链表 class List: NSObject { var value: Any? var next: List? } var listStack: List? //栈的当前节点 var curList: List? //栈的大小 var size: Int? //栈中元素个数 var count: Int? init(size: Int) { self.count = 0 self.size = size //初始化带头链表 self.listStack = List.init() self.curList = self.listStack } } ``` 1.2进栈 ```objectivec /// 进栈 /// - Parameter data: 进栈数据 /// - Returns: 进栈结果 func push(data: Any) -> Bool { if count == size { //栈满了 return false }else { let newList = List.init() newList.value = data curList?.next = newList curList = curList?.next count! += 1 return true } } ``` 1.3出栈 ```objectivec /// 出栈 /// - Returns: 出栈数据 func pop() -> Any? { if count == 0 { //栈里面没数据 return nil }else { let data = curList?.value var tempList = listStack while tempList?.next?.next != nil { //获取倒数第二个节点 tempList = tempList?.next } curList = tempList //删除最后一个节点 curList?.next = nil count! -= 1 return data } } ```