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Commit 6fc66ea

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Completed hash table implementation (#6 IP)
1 parent 7f68a70 commit 6fc66ea

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3 files changed

+114
-1
lines changed

3 files changed

+114
-1
lines changed

‎Data-Structures/Arrays/My_Array_Implementation.ts renamed to ‎Data-Structures/Arrays/Implementation.ts

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// RUN: deno run Data-Structures/Arrays/My_Array_Implementation.ts
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// RUN: deno run Data-Structures/Arrays/Implementation.ts
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type NumIndexedObject = { [index: number]: any };
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// RUN: deno run Data-Structures/Hash-Tables/Implementation.ts
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class HashTable {
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private size: number;
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private data: Array<Array<any>>;
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constructor(numBuckets: number) {
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this.size = numBuckets;
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this.data = new Array(numBuckets);
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}
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public set(key: string, value: any): void {
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let address = this._hash(key);
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if (!this.data[address]) {
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this.data[address] = [];
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}
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this.data[address].push([key,value]);
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}
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public get(key: string): any {
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let address = this._hash(key);
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const currentBucket: any[] = this.data[address];
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if (currentBucket.length) {
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for(let item of currentBucket) {
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if (item[0] === key) return item[1];
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}
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}
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return undefined;
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}
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public keys(): string[] {
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const keysArray = new Array<string>();
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// Loop through all buckets
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for (let i=0; i < this.data.length; ++i) {
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// If bucket has item(s)
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if (this.data[i]) {
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// Handle Collisions: Grab all keys from bucket
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// (incl. multiple items)
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for(let item of this.data[i]) {
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keysArray.push(item[0]);
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}
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}
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}
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return keysArray;
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}
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public values(): string[] {
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const valuesArray = new Array<string>();
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for (let i=0; i < this.data.length; ++i) {
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if (this.data[i]) {
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for(let item of this.data[i]) {
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valuesArray.push(item[1]);
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}
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}
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}
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return valuesArray;
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}
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public getSize(): number {
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return this.size;
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}
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private _hash(key: string) {
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let hash = 0;
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for (let i=0; i < key.length; ++i) {
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hash = (hash + key.charCodeAt(i) * i)
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% this.data.length;
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}
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return hash;
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}
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public testHashFunction() {
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console.log(hashTable._hash('grapes'));
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console.log(hashTable._hash('grapess'));
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console.log(hashTable._hash('grapes'));
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}
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}
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const hashTable = new HashTable(16);
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// hashTable.testHashFunction();
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hashTable.set('grapes', 27);
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hashTable.set('apples', 6);
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hashTable.set('tangerines', 12);
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console.log('apples:', hashTable.get('apples'));
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console.log('grapes:', hashTable.get('grapes'));
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console.log(hashTable.keys());
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console.log(hashTable.values());
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//Google Question
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//Given an array = [2,5,1,2,3,5,1,2,4]:
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//It should return 2
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//Given an array = [2,1,1,2,3,5,1,2,4]:
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//It should return 1
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//Given an array = [2,3,4,5]:
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//It should return undefined
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//Bonus... What if we had this:
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// [2,5,5,2,3,5,1,2,4]
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// return 5 because the pairs are before 2,2

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