hello-algo/codes/javascript/chapter_hashing/array_hash_map.js
Yudong Jin e720aa2d24
feat: Revised the book (#978)
* Sync recent changes to the revised Word.

* Revised the preface chapter

* Revised the introduction chapter

* Revised the computation complexity chapter

* Revised the chapter data structure

* Revised the chapter array and linked list

* Revised the chapter stack and queue

* Revised the chapter hashing

* Revised the chapter tree

* Revised the chapter heap

* Revised the chapter graph

* Revised the chapter searching

* Reivised the sorting chapter

* Revised the divide and conquer chapter

* Revised the chapter backtacking

* Revised the DP chapter

* Revised the greedy chapter

* Revised the appendix chapter

* Revised the preface chapter doubly

* Revised the figures
2023-12-02 06:21:34 +08:00

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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 Pair {
constructor(key, val) {
this.key = key;
this.val = val;
}
}
/* 基于数组实现的哈希表 */
class ArrayHashMap {
#buckets;
constructor() {
// 初始化数组,包含 100 个桶
this.#buckets = 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 pair = this.#buckets[index];
if (pair === null) return null;
return pair.val;
}
/* 添加操作 */
set(key, val) {
let index = this.#hashFunc(key);
this.#buckets[index] = new Pair(key, val);
}
/* 删除操作 */
delete(key) {
let index = this.#hashFunc(key);
// 置为 null ,代表删除
this.#buckets[index] = null;
}
/* 获取所有键值对 */
entries() {
let arr = [];
for (let i = 0; i < this.#buckets.length; i++) {
if (this.#buckets[i]) {
arr.push(this.#buckets[i]);
}
}
return arr;
}
/* 获取所有键 */
keys() {
let arr = [];
for (let i = 0; i < this.#buckets.length; i++) {
if (this.#buckets[i]) {
arr.push(this.#buckets[i].key);
}
}
return arr;
}
/* 获取所有值 */
values() {
let arr = [];
for (let i = 0; i < this.#buckets.length; i++) {
if (this.#buckets[i]) {
arr.push(this.#buckets[i].val);
}
}
return arr;
}
/* 打印哈希表 */
print() {
let pairSet = this.entries();
for (const pair of pairSet) {
console.info(`${pair.key} -> ${pair.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 pair of map.entries()) {
if (!pair) continue;
console.info(pair.key + ' -> ' + pair.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);
}