contains duplicate solution

Author: hanseulhee

contains-duplicate/hanseulhee.js

@@ -0,0 +1,17 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+
+var containsDuplicate = function(nums) {
+    const duplicate = new Set();
+
+    for (let i = 0; i < nums.length; i++) {
+        if (duplicate.has(nums[i])) {
+            return true;
+        }
+        duplicate.add(nums[i]);
+    }
+
+    return false;
+};