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/**
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* File: queue.js
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* Created Time: 2022-12-05
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* Author: S-N-O-R-L-A-X (snorlax.xu@outlook.com)
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*/
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/* Driver Code */
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/* 初始化队列 */
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// JavaScript 没有内置的队列，可以把 Array 当作队列来使用
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const queue = [];
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/* 元素入队 */
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queue.push(1);
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queue.push(3);
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queue.push(2);
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queue.push(5);
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queue.push(4);
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console.log('队列 queue =', queue);
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/* 访问队首元素 */
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const peek = queue[0];
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console.log('队首元素 peek =', peek);
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/* 元素出队 */
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// 底层是数组，因此 shift() 方法的时间复杂度为 O(n)
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const pop = queue.shift();
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console.log('出队元素 pop =', pop, '，出队后 queue = ', queue);
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/* 获取队列的长度 */
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const size = queue.length;
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console.log('队列长度 size =', size);
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/* 判断队列是否为空 */
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const isEmpty = queue.length === 0;
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console.log('队列是否为空 = ', isEmpty);
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