diff --git a/codes/typescript/chapter_stack_and_queue/linkedlist_queue.ts b/codes/typescript/chapter_stack_and_queue/linkedlist_queue.ts new file mode 100644 index 000000000..01e93b063 --- /dev/null +++ b/codes/typescript/chapter_stack_and_queue/linkedlist_queue.ts @@ -0,0 +1,103 @@ +/** + * File: linkedlist_queue.ts + * Created Time: 2022-12-19 + * Author: S-N-O-R-L-A-X (snorlax.xu@outlook.com) + */ + +import ListNode from "../module/ListNode" + +/* 基于链表实现的队列 */ +class LinkedListQueue { + private front: ListNode | null; + private rear: ListNode | null; // 头结点 front ,尾结点 rear + private queSize: number = 0; + + constructor() { + this.front = null; + this.rear = null; + } + + /* 获取队列的长度 */ + get size(): number { + return this.queSize; + } + + /* 判断队列是否为空 */ + isEmpty(): boolean { + return this.size === 0; + } + + /* 入队 */ + offer(num: number): void { + // 尾结点后添加 num + const node = new ListNode(num); + // 如果队列为空,则令头、尾结点都指向该结点 + if (!this.front) { + this.front = node; + this.rear = node; + // 如果队列不为空,则将该结点添加到尾结点后 + } else { + this.rear!.next = node; + this.rear = node; + } + this.queSize++; + } + + /* 出队 */ + poll(): number { + const num = this.peek(); + if (!this.front) { + throw new Error("No element in queue!") + } + // 删除头结点 + this.front = this.front.next; + this.queSize--; + return num; + } + + /* 访问队首元素 */ + peek(): number { + if (this.size === 0) + throw new Error("No element in queue!"); + return this.front!.val; + } + + /* 将链表转化为 Array 并返回 */ + toArray(): number[] { + let node = this.front; + const res = new Array(this.size); + for (let i = 0; i < res.length; i++) { + res[i] = node!.val; + node = node!.next; + } + return res; + } +} + + +/* 初始化队列 */ +const queue = new LinkedListQueue(); + +/* 元素入队 */ +queue.offer(1); +queue.offer(3); +queue.offer(2); +queue.offer(5); +queue.offer(4); +console.log("队列 queue = " + queue.toArray()); + +/* 访问队首元素 */ +const peek = queue.peek(); +console.log("队首元素 peek = " + peek); + +/* 元素出队 */ +const poll = queue.poll(); +console.log("出队元素 poll = " + poll + ",出队后 queue = " + queue.toArray()); + +/* 获取队列的长度 */ +const size = queue.size; +console.log("队列长度 size = " + size); + +/* 判断队列是否为空 */ +const isEmpty = queue.isEmpty(); +console.log("队列是否为空 = " + isEmpty);