Add solution #169

Author: JoshCrozier

README.md

@@ -62,6 +62,7 @@
 145|[Binary Tree Postorder Traversal](./0145-binary-tree-postorder-traversal.js)|Easy|
 151|[Reverse Words in a String](./0151-reverse-words-in-a-string.js)|Medium|
 152|[Maximum Product Subarray](./0152-maximum-product-subarray.js)|Medium|
+169|[Majority Element](./0169-majority-element.js)|Easy|
 179|[Largest Number](./0179-largest-number.js)|Medium|
 191|[Number of 1 Bits](./0191-number-of-1-bits.js)|Easy|
 203|[Remove Linked List Elements](./0203-remove-linked-list-elements.js)|Easy|

solutions/0169-majority-element.js

@@ -0,0 +1,22 @@
+/**
+ * 169. Majority Element
+ * https://leetcode.com/problems/majority-element/
+ * Difficulty: Easy
+ *
+ * Given an array nums of size n, return the majority element.
+ *
+ * The majority element is the element that appears more than ⌊n / 2⌋ times.
+ * You may assume that the majority element always exists in the array.
+ */
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var majorityElement = function(nums) {
+  const map = new Map();
+  nums.forEach(n => map.set(n, (map.get(n) || 0) + 1));
+
+  const sorted = [...map].sort(([,a], [,b]) => b - a);
+  return sorted[0][0];
+};