Create jewels-and-stones.cpp

Author: kamyu104

C++/jewels-and-stones.cpp

@@ -0,0 +1,17 @@
+// Time:  O(m + n)
+// Space: O(n)
+
+class Solution {
+public:
+    int numJewelsInStones(string J, string S) {
+        unordered_set<char> lookup;
+        for (const auto& j : J) {
+            lookup.emplace(j);
+        }
+        int result = 0;
+        for (const auto& s : S) {
+            result += lookup.count(s);
+        }
+        return result;
+    }
+};