Add solution #1684

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,471 LeetCode solutions in JavaScript
+# 1,472 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1296,6 +1296,7 @@
 1679|[Max Number of K-Sum Pairs](./solutions/1679-max-number-of-k-sum-pairs.js)|Medium|
 1680|[Concatenation of Consecutive Binary Numbers](./solutions/1680-concatenation-of-consecutive-binary-numbers.js)|Medium|
 1681|[Minimum Incompatibility](./solutions/1681-minimum-incompatibility.js)|Hard|
+1684|[Count the Number of Consistent Strings](./solutions/1684-count-the-number-of-consistent-strings.js)|Easy|
 1716|[Calculate Money in Leetcode Bank](./solutions/1716-calculate-money-in-leetcode-bank.js)|Easy|
 1718|[Construct the Lexicographically Largest Valid Sequence](./solutions/1718-construct-the-lexicographically-largest-valid-sequence.js)|Medium|
 1726|[Tuple with Same Product](./solutions/1726-tuple-with-same-product.js)|Medium|

solutions/1684-count-the-number-of-consistent-strings.js

@@ -0,0 +1,33 @@
+/**
+ * 1684. Count the Number of Consistent Strings
+ * https://leetcode.com/problems/count-the-number-of-consistent-strings/
+ * Difficulty: Easy
+ *
+ * You are given a string allowed consisting of distinct characters and an array of strings words.
+ * A string is consistent if all characters in the string appear in the string allowed.
+ *
+ * Return the number of consistent strings in the array words.
+ */
+
+/**
+ * @param {string} allowed
+ * @param {string[]} words
+ * @return {number}
+ */
+var countConsistentStrings = function(allowed, words) {
+  const allowedSet = new Set(allowed);
+  let result = 0;
+
+  for (const word of words) {
+    let isConsistent = true;
+    for (const char of word) {
+      if (!allowedSet.has(char)) {
+        isConsistent = false;
+        break;
+      }
+    }
+    if (isConsistent) result++;
+  }
+
+  return result;
+};