Add solution #705

Author: JoshCrozier

README.md

@@ -134,6 +134,7 @@
 700|[Search in a Binary Search Tree](./0700-search-in-a-binary-search-tree.js)|Easy|
 701|[Insert into a Binary Search Tree](./0701-insert-into-a-binary-search-tree.js)|Medium|
 704|[Binary Search](./0704-binary-search.js)|Easy|
+705|[Design HashSet](./0705-design-hashset.js)|Easy|
 706|[Design HashMap](./0706-design-hashmap.js)|Easy|
 713|[Subarray Product Less Than K](./0713-subarray-product-less-than-k.js)|Medium|
 722|[Remove Comments](./0722-remove-comments.js)|Medium|

solutions/0705-design-hashset.js

@@ -0,0 +1,42 @@
+/**
+ * 705. Design HashSet
+ * https://leetcode.com/problems/design-hashset/
+ * Difficulty: Easy
+ *
+ * Design a HashSet without using any built-in hash table libraries.
+ *
+ * Implement MyHashSet class:
+ * - void add(key) Inserts the value key into the HashSet.
+ * - bool contains(key) Returns whether the value key exists in the
+ *   HashSet or not.
+ * - void remove(key) Removes the value key in the HashSet. If key
+ *   does not exist in the HashSet, do nothing.
+ */
+
+var MyHashSet = function() {
+  this._keys = [];
+};
+
+/**
+ * @param {number} key
+ * @return {void}
+ */
+MyHashSet.prototype.add = function(key) {
+  this._keys[key] = 1;
+};
+
+/**
+ * @param {number} key
+ * @return {void}
+ */
+MyHashSet.prototype.remove = function(key) {
+  this._keys[key] = undefined;
+};
+
+/**
+ * @param {number} key
+ * @return {boolean}
+ */
+MyHashSet.prototype.contains = function(key) {
+  return this._keys[key] !== undefined;
+};