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| class Hashtable { | |
| constructor() { | |
| this._storage = []; | |
| this._storageLimit = 8; | |
| } | |
| insert(key, value) { | |
| let hash = getHash(key, this._storageLimit); | |
| this._storage[hash] ? this._storage[hash] = this._storage[hash] : | |
| this._storage[hash] = []; | |
| for (let i = 0; i < this._storage[hash].length; i++) { | |
| let tupple = this._storage[hash][i]; | |
| if (tupple[0] === key) { | |
| return 'key already exists; keys must be unique'; | |
| } | |
| } | |
| this._storage[hash].push([key, value]); | |
| return 'inserted'; | |
| } | |
| retrieve(key) { | |
| let hash = getHash(key, this._storageLimit); | |
| if (!this._storage[hash]) return 'key does not exist'; | |
| for (let i = 0; i < this._storage[hash].length; i++) { | |
| let tupple = this._storage[hash][i]; | |
| if (tupple[0] === key) { | |
| return tupple; | |
| } | |
| } | |
| } | |
| remove(key) { | |
| let hash = getHash(key, this._storageLimit); | |
| if (!this._storage[hash]) return 'key does not exist'; | |
| for (let i = 0; i < this._storage[hash].length; i++) { | |
| if (this._storage[hash][i][0] === key) { | |
| this._storage[hash][i].splice(i, 2); | |
| return key + ' removed'; | |
| } | |
| } | |
| } | |
| }; | |
| // helper function that generates hash | |
| var getHash = function (str, max) { | |
| let hash = 0; | |
| for (let i = 0; i < str.length; i++) { | |
| hash = (hash << 5) + hash + str.charCodeAt(i); | |
| hash = hash & hash; // | |
| hash = Math.abs(hash); | |
| } | |
| return hash % max; | |
| }; |
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hi @jenjwong, I have a question, I tried your code and it works fine.. but when I tried to look deeper, getHash function always return 0, so I remove the getHash func and it still works. Can you explain why the getHash always return 0, and what is that used for?