Add solution #1641

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,442 LeetCode solutions in JavaScript
+# 1,443 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1265,6 +1265,7 @@
 1638|[Count Substrings That Differ by One Character](./solutions/1638-count-substrings-that-differ-by-one-character.js)|Medium|
 1639|[Number of Ways to Form a Target String Given a Dictionary](./solutions/1639-number-of-ways-to-form-a-target-string-given-a-dictionary.js)|Hard|
 1640|[Check Array Formation Through Concatenation](./solutions/1640-check-array-formation-through-concatenation.js)|Easy|
+1641|[Count Sorted Vowel Strings](./solutions/1641-count-sorted-vowel-strings.js)|Medium|
 1657|[Determine if Two Strings Are Close](./solutions/1657-determine-if-two-strings-are-close.js)|Medium|
 1668|[Maximum Repeating Substring](./solutions/1668-maximum-repeating-substring.js)|Easy|
 1669|[Merge In Between Linked Lists](./solutions/1669-merge-in-between-linked-lists.js)|Medium|

solutions/1641-count-sorted-vowel-strings.js

@@ -0,0 +1,27 @@
+/**
+ * 1641. Count Sorted Vowel Strings
+ * https://leetcode.com/problems/count-sorted-vowel-strings/
+ * Difficulty: Medium
+ *
+ * Given an integer n, return the number of strings of length n that consist only of vowels
+ * (a, e, i, o, u) and are lexicographically sorted.
+ *
+ * A string s is lexicographically sorted if for all valid i, s[i] is the same as or comes
+ * before s[i+1] in the alphabet.
+ */
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var countVowelStrings = function(n) {
+  const vowelCounts = [1, 1, 1, 1, 1];
+
+  for (let i = 1; i < n; i++) {
+    for (let j = 3; j >= 0; j--) {
+      vowelCounts[j] += vowelCounts[j + 1];
+    }
+  }
+
+  return vowelCounts.reduce((sum, count) => sum + count, 0);
+};