Merge pull request #174 from justin-tse/dev-js-hash

Add the JavaScript code and docs for Chapter of Hash Map
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Yudong Jin 2022-12-27 00:01:08 +08:00 committed by GitHub
commit 4c9e5cca15
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3 changed files with 244 additions and 1 deletions

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/*
* File: array_hash_map.js
* Created Time: 2022-12-26
* Author: Justin (xiefahit@gmail.com)
*/
/* 键值对 Number -> String */
class Entry {
constructor(key, val) {
this.key = key;
this.val = val;
}
}
/* 基于数组简易实现的哈希表 */
class ArrayHashMap {
#bucket;
constructor() {
// 初始化一个长度为 100 的桶(数组)
this.#bucket = new Array(100).fill(null);
}
/* 哈希函数 */
#hashFunc(key) {
return key % 100;
}
/* 查询操作 */
get(key) {
let index = this.#hashFunc(key);
let entry = this.#bucket[index];
if (entry === null) return null;
return entry.val;
}
/* 添加操作 */
set(key, val) {
let index = this.#hashFunc(key);
this.#bucket[index] = new Entry(key, val);
}
/* 删除操作 */
delete(key) {
let index = this.#hashFunc(key);
// 置为 null ,代表删除
this.#bucket[index] = null;
}
/* 获取所有键值对 */
entries() {
let arr = [];
for (let i = 0; i < this.#bucket.length; i++) {
if (this.#bucket[i]) {
arr.push(this.#bucket[i]);
}
}
return arr;
}
/* 获取所有键 */
keys() {
let arr = [];
for (let i = 0; i < this.#bucket.length; i++) {
if (this.#bucket[i]) {
arr.push(this.#bucket[i]?.key);
}
}
return arr;
}
/* 获取所有值 */
values() {
let arr = [];
for (let i = 0; i < this.#bucket.length; i++) {
if (this.#bucket[i]) {
arr.push(this.#bucket[i]?.val);
}
}
return arr;
}
/* 打印哈希表 */
print() {
let entrySet = this.entries();
for (const entry of entrySet) {
if (!entry) continue;
console.info(`${entry.key} -> ${entry.val}`);
}
}
}
/* Driver Code */
/* 初始化哈希表 */
const map = new ArrayHashMap();
/* 添加操作 */
// 在哈希表中添加键值对 (key, value)
map.set(12836, '小哈');
map.set(15937, '小啰');
map.set(16750, '小算');
map.set(13276, '小法');
map.set(10583, '小鸭');
console.info('\n添加完成后哈希表为\nKey -> Value');
map.print();
/* 查询操作 */
// 向哈希表输入键 key ,得到值 value
let name = map.get(15937);
console.info('\n输入学号 15937 ,查询到姓名 ' + name);
/* 删除操作 */
// 在哈希表中删除键值对 (key, value)
map.delete(10583);
console.info('\n删除 10583 后,哈希表为\nKey -> Value');
map.print();
/* 遍历哈希表 */
console.info('\n遍历键值对 Key->Value');
for (const entry of map.entries()) {
if (!entry) continue;
console.info(entry.key + ' -> ' + entry.val);
}
console.info('\n单独遍历键 Key');
for (const key of map.keys()) {
console.info(key);
}
console.info('\n单独遍历值 Value');
for (const val of map.values()) {
console.info(val);
}

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/*
* File: hash_map.js
* Created Time: 2022-12-26
* Author: Justin (xiefahit@gmail.com)
*/
/* Driver Code */
/* 初始化哈希表 */
const map = new Map();
/* 添加操作 */
// 在哈希表中添加键值对 (key, value)
map.set(12836, '小哈');
map.set(15937, '小啰');
map.set(16750, '小算');
map.set(13276, '小法');
map.set(10583, '小鸭');
console.info('\n添加完成后哈希表为\nKey -> Value');
console.info(map);
/* 查询操作 */
// 向哈希表输入键 key ,得到值 value
let name = map.get(15937);
console.info('\n输入学号 15937 ,查询到姓名 ' + name);
/* 删除操作 */
// 在哈希表中删除键值对 (key, value)
map.delete(10583);
console.info('\n删除 10583 后,哈希表为\nKey -> Value');
console.info(map);
/* 遍历哈希表 */
console.info('\n遍历键值对 Key->Value');
for (const [k, v] of map.entries()) {
console.info(k + ' -> ' + v);
}
console.info('\n单独遍历键 Key');
for (const k of map.keys()) {
console.info(k);
}
console.info('\n单独遍历值 Value');
for (const v of map.values()) {
console.info(v);
}

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@ -132,7 +132,23 @@ comments: true
=== "JavaScript"
```js title="hash_map.js"
/* 初始化哈希表 */
const map = new ArrayHashMap();
/* 添加操作 */
// 在哈希表中添加键值对 (key, value)
map.set(12836, '小哈');
map.set(15937, '小啰');
map.set(16750, '小算');
map.set(13276, '小法');
map.set(10583, '小鸭');
/* 查询操作 */
// 向哈希表输入键 key ,得到值 value
let name = map.get(15937);
/* 删除操作 */
// 在哈希表中删除键值对 (key, value)
map.delete(10583);
```
=== "TypeScript"
@ -265,7 +281,20 @@ comments: true
=== "JavaScript"
```js title="hash_map.js"
/* 遍历哈希表 */
// 遍历键值对 key->value
for (const entry of map.entries()) {
if (!entry) continue;
console.info(entry.key + ' -> ' + entry.val);
}
// 单独遍历键 key
for (const key of map.keys()) {
console.info(key);
}
// 单独遍历值 value
for (const val of map.values()) {
console.info(val);
}
```
=== "TypeScript"
@ -533,7 +562,48 @@ $$
=== "JavaScript"
```js title="array_hash_map.js"
/* 键值对 Number -> String */
class Entry {
constructor(key, val) {
this.key = key;
this.val = val;
}
}
/* 基于数组简易实现的哈希表 */
class ArrayHashMap {
#bucket;
constructor() {
// 初始化一个长度为 100 的桶(数组)
this.#bucket = new Array(100).fill(null);
}
/* 哈希函数 */
#hashFunc(key) {
return key % 100;
}
/* 查询操作 */
get(key) {
let index = this.#hashFunc(key);
let entry = this.#bucket[index];
if (entry === null) return null;
return entry.val;
}
/* 添加操作 */
set(key, val) {
let index = this.#hashFunc(key);
this.#bucket[index] = new Entry(key, val);
}
/* 删除操作 */
delete(key) {
let index = this.#hashFunc(key);
// 置为 null ,代表删除
this.#bucket[index] = null;
}
}
```
=== "TypeScript"