概述
- 数据尾部进入
- 数据头部移除
特色
- First-In-First-Out 先进后出
完成一个简单的行列
完成一个简单的行列数据类型(基于数组)
export default function Queue() {
this.dataStore = [];
}
Queue.prototype.enqueue = function(elment) {
this.dataStore.push(elment)
}
Queue.prototype.dequeue = function() {
return this.dataStore.shift()
}
Queue.prototype.front = function() {
return this.dataStore[0]
}
Queue.prototype.back = function() {
return this.dataStore[this.dataStore.length - 1]
}
Queue.prototype.toString = function() {
let retStr = "";
for (let i = 0; i < this.dataStore.length; ++i) {
retStr += this.dataStore[i] + "\n";
}
return retStr
}
Queue.prototype.empty = function() {
if(this.dataStore.length === 0) {
return true
} else {
return false
}
}
下面是通过 Jest 的测验用例
装备 jest
npm install jest
$ ./node_modules/jest/bin/jest.js --init # 运用 jest 提供的指令主动初始化
考虑到现在 es module 现已开始遍及,此刻运用 esm 比较合适,在初始化的时候注意选择与 esm 的选项。同时 package.json 的内容中:
{
"type": "module",
}
- 测验用例中,运用测验套件 describe/测验用例 it, 运用 spec 符号是测验文件
测验用例
import Queue from "../Queue"
describe("api 测验", () => {
it("toString 办法测验", () => {
let q = new Queue()
q.enqueue('张三')
q.enqueue('李四')
q.enqueue('王五')
expect(q.toString()).toMatchInlineSnapshot(`
"张三
李四
王五
"
`)
})
it("dequeue 办法测验", () => {
let q = new Queue()
q.enqueue('张三')
q.enqueue('李四')
q.enqueue('王五')
q.dequeue()
expect(q.toString()).toMatchInlineSnapshot(`
"李四
王五
"
`)
})
it("front/back 办法测验", () => {
let q = new Queue()
q.enqueue('张三')
q.enqueue('李四')
q.enqueue('王五')
q.dequeue()
expect(q.front()).toMatchInlineSnapshot(`"李四"`)
expect(q.back()).toMatchInlineSnapshot(`"王五"`)
})
})
三个示例
- 方块舞的舞伴分配问题
方块舞的舞伴分配问题
import fs from 'node:fs'
export default function Queue() {
this.dataStore = [];
}
Queue.prototype.enqueue = function(elment) {
this.dataStore.push(elment)
}
Queue.prototype.dequeue = function() {
return this.dataStore.shift()
}
Queue.prototype.front = function() {
return this.dataStore[0]
}
Queue.prototype.back = function() {
return this.dataStore[this.dataStore.length - 1]
}
Queue.prototype.toString = function() {
let retStr = "";
for (let i = 0; i < this.dataStore.length; ++i) {
retStr += this.dataStore[i] + "\n";
}
return retStr
}
Queue.prototype.empty = function() {
if(this.dataStore.length === 0) {
return true
} else {
return false
}
}
Queue.prototype.count = function() {
return this.dataStore.lastIndexOf.length;
}
- 完成跳舞人分配
export let maleDancers = new Queue()
export let femaleDancers = new Queue()
export function Dancer(name, sex) {
this.name = name;
this.sex = sex;
}
export function getDancers(maleDancers, femaleDancers) {
let names = read(join(__dirname, './texts/dancers.txt')).split('\n')
for (let i = 0; i < names.length; ++i) {
names[i] = names[i].trim()
}
for (let i = 0; i < names.length; ++i) {
let dancer = names[i].split(" ");
let sex = dancer[0];
let name = dancer[1];
if(sex == 'F') {
femaleDancers.enqueue(new Dancer(name, sex))
} else {
maleDancers.enqueue(new Dancer(name, sex))
}
}
console.log('males', femaleDancers, maleDancers)
}
export function dance(males, females) {
console.log("这个舞者的伴侣时: \n");
while(!females.empty() && !males.empty()) {
let fperson = females.dequeue();
let mperson = males.dequeue();
console.log(`男舞者是:${mperson.name}, 对应的女舞者是:${fperson.name}`)
}
console.log('')
}
export function read(path) {
let dancersContent = fs.readFileSync(path, {
encoding: 'utf-8'
})
return dancersContent
}
- 编写测验用例
import { dirname, join } from "node:path";
import { fileURLToPath } from "url";
import Queue, { getDancers, read, /* maleDancers, femaleDancers, */dance } from "../Queue";
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
describe("测验舞伴匹配", () => {
it("dancers", () => {
let maleDancers = new Queue();
let femaleDancers = new Queue();
getDancers(maleDancers, femaleDancers);
expect(maleDancers).toMatchInlineSnapshot(`
Queue {
"dataStore": [
Dancer {
"name": "李四",
"sex": "M",
},
Dancer {
"name": "王五",
"sex": "M",
},
Dancer {
"name": "赵六",
"sex": "M",
},
Dancer {
"name": "周八",
"sex": "M",
},
Dancer {
"name": "郑十",
"sex": "M",
},
Dancer {
"name": "王一",
"sex": "M",
},
Dancer {
"name": "刘二",
"sex": "M",
},
],
}
`);
expect(femaleDancers).toMatchInlineSnapshot(`
Queue {
"dataStore": [
Dancer {
"name": "张三(女)",
"sex": "F",
},
Dancer {
"name": "孙七(女)",
"sex": "F",
},
Dancer {
"name": "吴九(女)",
"sex": "F",
},
Dancer {
"name": "钱一(女)",
"sex": "F",
},
],
}
`);
dance(maleDancers, femaleDancers);
expect(maleDancers).toMatchInlineSnapshot(`
Queue {
"dataStore": [
Dancer {
"name": "郑十",
"sex": "M",
},
Dancer {
"name": "王一",
"sex": "M",
},
Dancer {
"name": "刘二",
"sex": "M",
},
],
}
`);
expect(femaleDancers).toMatchInlineSnapshot(`
Queue {
"dataStore": [],
}
`);
});
});
写到这里,发现书本里边其实也是有过错存在的。所以书是用来体系学习的。真正的掌握还要看自己。
基数排序
添加三个辅佐办法
// 可选 个位数,十位数 来排序
export const distrbute = function(nums, queues, n, digit) {
for (let i = 0; i < n; ++i) {
if (digit == 1) {
queues[nums[i] % 10].enqueue(nums[i]);
} else {
queues[Math.floor(nums[i] / 10)].enqueue(num[i])
}
}
}
// 收集元素
export const collect = function(queues, nums) {
let i = 0;
for (let digit = 0; digit < 10; ++digit) {
while (!queues[digit].empty()) {
nums[i++] = queues[digit].dequeue()
}
}
}
// 展现元素:因为运用测验用例,展现运用快照
export const dispArray = function(arr) {
for (let i = 0; i < arr.length; ++i) {
console.log(arr[i] + " ")
}
}
测验用例
describe("基数排序测验", () => {
it("基数算法", () => {
let queues = [];
for (let i = 0; i < 10; ++i) {
queues[i] = new Queue();
}
let nums = [];
for (let i = 0; i < 10; ++i) {
nums[i] = Math.floor(Math.floor(Math.random() * 101));
}
dispArray(nums);
expect(nums).toMatchInlineSnapshot(`
[
71,
78,
61,
91,
21,
2,
24,
38,
71,
37,
]
`);
distrbute(nums, queues, 10, 1);
collect(queues, nums);
(nums, queues, 10, 10);
collect(queues, nums);
expect(nums).toMatchInlineSnapshot(`
[
2,
21,
24,
37,
38,
61,
71,
71,
78,
91,
]
`);
});
});
小结
- 理解行列,以及行列与列表的差异。列表
先进后出
,行列先进先出
。 - 行列特色是:从
尾部插入
,从头部删除
。 - 其次便是 Queue api的设:
属性
和办法
。 - 完成了两个示例:一个是在行列平分配舞伴,一个是基数排序。同时运用 Jest 作为测验工具(如:快照测验)。