129 lines
3.0 KiB
JavaScript
129 lines
3.0 KiB
JavaScript
/**
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* File: array_hash_map.js
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* Created Time: 2022-12-26
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* Author: Justin (xiefahit@gmail.com)
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*/
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/* Key-value pair Number -> String */
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class Pair {
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constructor(key, val) {
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this.key = key;
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this.val = val;
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}
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}
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/* Hash table based on array implementation */
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class ArrayHashMap {
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#buckets;
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constructor() {
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// Initialize an array, containing 100 buckets
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this.#buckets = new Array(100).fill(null);
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}
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/* Hash function */
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#hashFunc(key) {
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return key % 100;
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}
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/* Query operation */
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get(key) {
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let index = this.#hashFunc(key);
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let pair = this.#buckets[index];
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if (pair === null) return null;
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return pair.val;
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}
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/* Add operation */
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set(key, val) {
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let index = this.#hashFunc(key);
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this.#buckets[index] = new Pair(key, val);
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}
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/* Remove operation */
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delete(key) {
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let index = this.#hashFunc(key);
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// Set to null, indicating removal
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this.#buckets[index] = null;
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}
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/* Get all key-value pairs */
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entries() {
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let arr = [];
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for (let i = 0; i < this.#buckets.length; i++) {
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if (this.#buckets[i]) {
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arr.push(this.#buckets[i]);
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}
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}
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return arr;
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}
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/* Get all keys */
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keys() {
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let arr = [];
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for (let i = 0; i < this.#buckets.length; i++) {
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if (this.#buckets[i]) {
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arr.push(this.#buckets[i].key);
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}
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}
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return arr;
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}
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/* Get all values */
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values() {
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let arr = [];
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for (let i = 0; i < this.#buckets.length; i++) {
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if (this.#buckets[i]) {
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arr.push(this.#buckets[i].val);
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}
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}
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return arr;
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}
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/* Print hash table */
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print() {
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let pairSet = this.entries();
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for (const pair of pairSet) {
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console.info(`${pair.key} -> ${pair.val}`);
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}
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}
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}
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/* Driver Code */
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/* Initialize hash table */
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const map = new ArrayHashMap();
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/* Add operation */
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// Add key-value pair (key, value) to the hash table
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map.set(12836, 'Ha');
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map.set(15937, 'Luo');
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map.set(16750, 'Suan');
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map.set(13276, 'Fa');
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map.set(10583, 'Ya');
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console.info('\nAfter adding, the hash table is\nKey -> Value');
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map.print();
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/* Query operation */
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// Enter key to the hash table, get value
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let name = map.get(15937);
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console.info('\nEnter student ID 15937, found name ' + name);
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/* Remove operation */
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// Remove key-value pair (key, value) from the hash table
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map.delete(10583);
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console.info('\nAfter removing 10583, the hash table is\nKey -> Value');
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map.print();
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/* Traverse hash table */
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console.info('\nTraverse key-value pairs Key->Value');
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for (const pair of map.entries()) {
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if (!pair) continue;
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console.info(pair.key + ' -> ' + pair.val);
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}
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console.info('\nIndividually traverse keys Key');
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for (const key of map.keys()) {
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console.info(key);
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}
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console.info('\nIndividually traverse values Value');
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for (const val of map.values()) {
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console.info(val);
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}
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