Add solution #2047

Author: JoshCrozier

README.md

@@ -216,6 +216,7 @@
 2000|[Reverse Prefix of Word](./2000-reverse-prefix-of-word.js)|Easy|
 2011|[Final Value of Variable After Performing Operations](./2011-final-value-of-variable-after-performing-operations.js)|Easy|
 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|
 
 ## License
 

solutions/2047-number-of-valid-words-in-a-sentence.js

@@ -0,0 +1,31 @@
+/**
+ * 2047. Number of Valid Words in a Sentence
+ * https://leetcode.com/problems/number-of-valid-words-in-a-sentence/
+ * Difficulty: Easy
+ *
+ * A sentence consists of lowercase letters ('a' to 'z'), digits ('0' to '9'),
+ * hyphens ('-'), punctuation marks ('!', '.', and ','), and spaces (' ') only.
+ * Each sentence can be broken down into one or more tokens separated by one or
+ * more spaces ' '.
+ *
+ * A token is a valid word if all three of the following are true:
+ * - It only contains lowercase letters, hyphens, and/or punctuation (no digits).
+ * - There is at most one hyphen '-'. If present, it must be surrounded by lowercase
+ *   characters ("a-b" is valid, but "-ab" and "ab-" are not valid).
+ * - There is at most one punctuation mark. If present, it must be at the end of
+ *   the token ("ab,", "cd!", and "." are valid, but "a!b" and "c.," are not valid).
+ *
+ * Examples of valid words include "a-b.", "afad", "ba-c", "a!", and "!".
+ *
+ * Given a string sentence, return the number of valid words in sentence.
+ */
+
+/**
+ * @param {string} sentence
+ * @return {number}
+ */
+var countValidWords = function(sentence) {
+  return sentence.trim().split(/\s+/).reduce((total, str) => {
+    return total + (/^(?:([a-z]+\-?[a-z]+)|([a-z+]))?[!.,]?$/.test(str) ? 1 : 0);
+  }, 0);
+};