摘要：
interface NodeItem { prev: NodeItem | null next: NodeItem | null data: any } class NodeItem { prev: NodeItem | null = null next: NodeItem | null = nul 阅读全文
摘要：
interface Stack { _items: any push(element: any): void pop(): any top(): any size(): any isEmpty(): any clear(): any } //用Symbol添加私有属性 class Stack { _ 阅读全文