Add solution #260

Author: JoshCrozier

README.md

@@ -205,6 +205,7 @@
 237|[Delete Node in a Linked List](./0237-delete-node-in-a-linked-list.js)|Easy|
 238|[Product of Array Except Self](./0238-product-of-array-except-self.js)|Medium|
 242|[Valid Anagram](./0242-valid-anagram.js)|Easy|
+260|[Single Number III](./0260-single-number-iii.js)|Medium|
 263|[Ugly Number](./0263-ugly-number.js)|Easy|
 264|[Ugly Number II](./0264-ugly-number-ii.js)|Medium|
 268|[Missing Number](./0268-missing-number.js)|Easy|

solutions/0260-single-number-iii.js

@@ -0,0 +1,19 @@
+/**
+ * 260. Single Number III
+ * https://leetcode.com/problems/single-number-iii/
+ * Difficulty: Medium
+ *
+ * Given an integer array nums, in which exactly two elements appear only once and all
+ * the other elements appear exactly twice. Find the two elements that appear only once.
+ * You can return the answer in any order.
+ */
+
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var singleNumber = function(nums) {
+  const set = new Set();
+  nums.forEach(n => set.has(n) ? set.delete(n) : set.add(n));
+  return Array.from(set);
+};