Add solution #771

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,399 LeetCode solutions in JavaScript
+# 1,400 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -591,6 +591,7 @@
 768|[Max Chunks To Make Sorted II](./solutions/0768-max-chunks-to-make-sorted-ii.js)|Hard|
 769|[Max Chunks To Make Sorted](./solutions/0769-max-chunks-to-make-sorted.js)|Medium|
 770|[Basic Calculator IV](./solutions/0770-basic-calculator-iv.js)|Hard|
+771|[Jewels and Stones](./solutions/0771-jewels-and-stones.js)|Easy|
 773|[Sliding Puzzle](./solutions/0773-sliding-puzzle.js)|Hard|
 775|[Global and Local Inversions](./solutions/0775-global-and-local-inversions.js)|Medium|
 777|[Swap Adjacent in LR String](./solutions/0777-swap-adjacent-in-lr-string.js)|Medium|

solutions/0771-jewels-and-stones.js

@@ -0,0 +1,29 @@
+/**
+ * 771. Jewels and Stones
+ * https://leetcode.com/problems/jewels-and-stones/
+ * Difficulty: Easy
+ *
+ * You're given strings jewels representing the types of stones that are jewels, and stones
+ * representing the stones you have. Each character in stones is a type of stone you have.
+ * You want to know how many of the stones you have are also jewels.
+ *
+ * Letters are case sensitive, so "a" is considered a different type of stone from "A".
+ */
+
+/**
+ * @param {string} jewels
+ * @param {string} stones
+ * @return {number}
+ */
+var numJewelsInStones = function(jewels, stones) {
+  const set = new Set(jewels);
+  let result = 0;
+
+  for (const stone of stones) {
+    if (set.has(stone)) {
+      result++;
+    }
+  }
+
+  return result;
+};