Add solution #2085

Author: JoshCrozier

README.md

@@ -245,6 +245,7 @@
 2016|[Maximum Difference Between Increasing Elements](./2016-maximum-difference-between-increasing-elements.js)|Easy|
 2047|[Number of Valid Words in a Sentence](./2047-number-of-valid-words-in-a-sentence.js)|Easy|
 2053|[Kth Distinct String in an Array](./2053-kth-distinct-string-in-an-array.js)|Medium|
+2085|[Count Common Words With One Occurrence](./2085-count-common-words-with-one-occurrence.js)|Easy|
 2095|[Delete the Middle Node of a Linked List](./2095-delete-the-middle-node-of-a-linked-list.js)|Medium|
 2114|[Maximum Number of Words Found in Sentences](./2114-maximum-number-of-words-found-in-sentences.js)|Easy|
 

solutions/2085-count-common-words-with-one-occurrence.js

@@ -0,0 +1,22 @@
+/**
+ * 2085. Count Common Words With One Occurrence
+ * https://leetcode.com/problems/count-common-words-with-one-occurrence/
+ * Difficulty: Easy
+ *
+ * Given two string arrays words1 and words2, return the number of strings
+ * that appear exactly once in each of the two arrays.
+ */
+
+/**
+ * @param {string[]} words1
+ * @param {string[]} words2
+ * @return {number}
+ */
+var countWords = function(words1, words2) {
+  const map = new Map();
+  words1.forEach(n => map.set(n, (map.get(n) || 0) + 1));
+  [...map].forEach(([key, count]) => count !== 1 ? map.delete(key) : null);
+  words2.forEach(n => map.has(n) ? map.set(n, (map.get(n) || 0) + 1) : null);
+
+  return [...map].filter(([, count]) => count === 2).length;
+};