Created hash table classes

Bishop92 · Bishop92 · commit f3ca50a67bf7 · 2014-04-07T23:13:06.000+02:00
diff --git a/HashTable/HashTable.js b/HashTable/HashTable.js
@@ -0,0 +1,105 @@
+/**
+ * Created by Stefano on 05/04/2014.
+ */
+
+/**
+ * Class for managing an hash table.
+ * @param size {number} The size of the table.
+ * @constructor
+ */
+function HashTable(size) {
+	/**
+	 * The size of the table
+	 * @type {number}
+	 */
+	this.size = size;
+
+	this.p = 1000;
+
+	this.a = Math.floor(Math.random() * this.p);
+
+	this.b = Math.floor(Math.random() * this.p);
+
+	/**
+	 * Calculate the hash of the param key.
+	 * @param key {number} The key to hash.
+	 * @return {number} The hash of the key.
+	 */
+	this.hash = function (key) {
+		return ((this.a * key + this.b) % this.p) % this.size;
+	};
+
+	/**
+	 * The items stored in the hash table.
+	 * @type {Array<DoubleLinkedList>}
+	 */
+	this.items = [];
+
+	for (var i = 0; i < size; i++)
+		this.items[i] = new DoubleLinkedList();
+}
+
+/**
+ * Store the item with its key.
+ * @param key {number} The key relatives to the item.
+ * @param item {*} The item to store.
+ */
+HashTable.prototype.insert = function (key, item) {
+	this.items[this.hash(key)].pushBack({key: key, item: item});
+};
+
+/**
+ * Delete the first item relatives to the key value.
+ * @param key {number} The key to delete.
+ * @return {void}
+ */
+HashTable.prototype.deleteKey = function (key) {
+	var list = this.items[this.hash(key)];
+	var it = list.getIterator();
+	for (it.first(); !it.isDone() && it.getItem().key !== key;)
+		it.next();
+	if (!it.isDone())
+		list.deleteNode(it.getNode());
+};
+
+/**
+ * Delete all the items relative to the key value.
+ * @param key {number} The key to delete.
+ * @return {void}
+ */
+HashTable.prototype.deleteAllKey = function (key) {
+	var list = this.items[this.hash(key)];
+	var it = list.getIterator();
+	for (it.first(); !it.isDone(); it.next())
+		if (it.getItem().key === key)
+			list.deleteNode(it.getNode());
+};
+
+/**
+ * Search the item relative to the key value.
+ * @param key {number} The key of the item to search.
+ * @return {*|undefined} The item found or undefined if the key does not exist.
+ */
+HashTable.prototype.search = function (key) {
+	var list = this.items[this.hash(key)];
+	var it = list.getIterator();
+	for (it.first(); !it.isDone(); it.next())
+		if (it.getItem().key === key)
+			return it.getItem().item;
+	return undefined;
+};
+
+/**
+ * Search all the items relative to the key value.
+ * @param key {number} The key of the items to search.
+ * @return {Array.<*>} An array with the items found.
+ */
+HashTable.prototype.searchAll = function (key) {
+	var list = this.items[this.hash(key)];
+	var it = list.getIterator();
+	var array = [];
+	for (it.first(); !it.isDone(); it.next())
+		if (it.getItem().key === key)
+			array.push(it.getItem().item);
+	return array;
+};
