Merge pull request neetcode-gh#265 from dev-goutham/217

97ms solution using sets

Author: neetcode-gh

javascript/217-Contains-Duplicate.js

@@ -3,14 +3,12 @@
  * @return {boolean}
  */
 var containsDuplicate = function(nums) {
-    let map = {};
-    
-    for (let i = 0; i < nums.length; i++) {
-        if (nums[i] in map) {
-            return true;
-        } else {
-            map[nums[i]] = i;
-        }
+    const numsSet =  new Set()
+    for(const i of nums){
+        if(numsSet.has(i)){
+            return true
+        } 
+        numsSet.add(i)
     }
-    return false;
-};
+    return false
+};