Hash Table using Separate Chaining 🐛

Author: deadcoder0904

examples/datastructures/hash-table-separate-chaining.js

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+class HashTable {
+	constructor() {
+		this.table = new Array(137);
+		this.buildChains();
+	}
+
+	betterHash(word) {
+		let total = 0;
+		for(let i = 0; i < word.length; i++)
+			total = 37 * total + word.toLowerCase().charCodeAt(i);
+		return total % this.table.length;
+	}
+
+	buildChains() {
+		for (let i = 0; i < this.table.length; i++)
+			this.table[i] = [];
+	}
+
+	put(value) {
+		const pos = this.betterHash(value);
+		let index = 0;
+		while(index < this.table.length && this.table[pos][index] != undefined)
+			index++;
+		this.table[pos][index] = value;
+	}
+
+	get(value) {
+		const hash = this.betterHash(value);
+		let index = 0;
+		while(index < this.table.length && this.table[hash][index] != value)
+			index++;
+		return this.table[hash][index];
+	}
+
+	showAll() {
+		let str = "";
+		for (let i = 0; i < this.table.length && this.table[i] !=undefined; i++)
+			for (let j = 0; j < this.table[i].length && this.table[i][j] !=undefined; j++)
+				str += i + " : " + this.table[i] + "\n";
+		return str;
+	}
+}
+
+module.exports = HashTable;

test/datastructures/hash-table-separate-chaining.test.js

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+const expect = require('chai').expect;
+const HashTable = require('../../examples/datastructures/hash-table-separate-chaining');
+
+describe('=> HASH TABLE USING SEPARATE CHAINING', function() {
+	let names;
+	before(function () {
+		names = new HashTable();
+	});
+
+	it('should create an Empty Hash Table', function(done) {
+		expect(names.table.length).to.deep.equal(137);
+		done();
+	});
+
+	it('should put value into the Hash Table',function() {
+		names.put("Diana");
+		names.put("Clayton");
+		names.put("Raymond");
+		names.put("Nadia");
+		names.put("Afzar");
+		expect(names.showAll()).to.equal("11 : Diana\n41 : Afzar\n56 : Clayton\n60 : Raymond\n129 : Nadia\n");
+	});
+
+	it('should get value from the Hash Table',function() {
+		expect(names.get("Nadia")).to.equal("Nadia");
+		expect(names.get("Diana")).to.equal("Diana");
+		expect(names.get("Azhar")).to.equal(undefined);
+	});
+
+});