Create 448-find-all-numbers-disappeared-in-an-array.js

Solved find-all-numbers-disappeared-in-an-array in JS.

Author: aadil42

javascript/448-find-all-numbers-disappeared-in-an-array.js

@@ -0,0 +1,19 @@
+// problem link https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array
+// time complexity O(n)
+
+var findDisappearedNumbers = function(nums) {
+    
+    const numberSet = new Set();
+
+    for(let i = 1; i < nums.length + 1; i++) {
+        numberSet.add(i);
+    }
+
+    nums.forEach((element) => {
+        if(numberSet.has(element)) {
+            numberSet.delete(element);
+        }
+    });
+
+    return Array.from(numberSet);
+};