mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 00:46:28 +08:00
f68bbb0d59
* Revised the book * Update the book with the second revised edition * Revise base on the manuscript of the first edition
106 lines
2.6 KiB
JavaScript
106 lines
2.6 KiB
JavaScript
/**
|
|
* File: array_queue.js
|
|
* Created Time: 2022-12-13
|
|
* Author: S-N-O-R-L-A-X (snorlax.xu@outlook.com)
|
|
*/
|
|
|
|
/* 基于环形数组实现的队列 */
|
|
class ArrayQueue {
|
|
#nums; // 用于存储队列元素的数组
|
|
#front = 0; // 队首指针，指向队首元素
|
|
#queSize = 0; // 队列长度
|
|
|
|
constructor(capacity) {
|
|
this.#nums = new Array(capacity);
|
|
}
|
|
|
|
/* 获取队列的容量 */
|
|
get capacity() {
|
|
return this.#nums.length;
|
|
}
|
|
|
|
/* 获取队列的长度 */
|
|
get size() {
|
|
return this.#queSize;
|
|
}
|
|
|
|
/* 判断队列是否为空 */
|
|
isEmpty() {
|
|
return this.#queSize === 0;
|
|
}
|
|
|
|
/* 入队 */
|
|
push(num) {
|
|
if (this.size === this.capacity) {
|
|
console.log('队列已满');
|
|
return;
|
|
}
|
|
// 计算队尾指针，指向队尾索引 + 1
|
|
// 通过取余操作实现 rear 越过数组尾部后回到头部
|
|
const rear = (this.#front + this.size) % this.capacity;
|
|
// 将 num 添加至队尾
|
|
this.#nums[rear] = num;
|
|
this.#queSize++;
|
|
}
|
|
|
|
/* 出队 */
|
|
pop() {
|
|
const num = this.peek();
|
|
// 队首指针向后移动一位，若越过尾部，则返回到数组头部
|
|
this.#front = (this.#front + 1) % this.capacity;
|
|
this.#queSize--;
|
|
return num;
|
|
}
|
|
|
|
/* 访问队首元素 */
|
|
peek() {
|
|
if (this.isEmpty()) throw new Error('队列为空');
|
|
return this.#nums[this.#front];
|
|
}
|
|
|
|
/* 返回 Array */
|
|
toArray() {
|
|
// 仅转换有效长度范围内的列表元素
|
|
const arr = new Array(this.size);
|
|
for (let i = 0, j = this.#front; i < this.size; i++, j++) {
|
|
arr[i] = this.#nums[j % this.capacity];
|
|
}
|
|
return arr;
|
|
}
|
|
}
|
|
|
|
/* Driver Code */
|
|
/* 初始化队列 */
|
|
const capacity = 10;
|
|
const queue = new ArrayQueue(capacity);
|
|
|
|
/* 元素入队 */
|
|
queue.push(1);
|
|
queue.push(3);
|
|
queue.push(2);
|
|
queue.push(5);
|
|
queue.push(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 pop = queue.pop();
|
|
console.log('出队元素 pop = ' + pop + '，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);
|
|
|
|
/* 测试环形数组 */
|
|
for (let i = 0; i < 10; i++) {
|
|
queue.push(i);
|
|
queue.pop();
|
|
console.log('第 ' + i + ' 轮入队 + 出队后 queue =', queue.toArray());
|
|
}
|