Missing Number

Author: Sunjae95

missing-number/sunjae95.js

@@ -0,0 +1,18 @@
+/**
+ * @description
+ * brainstorming:
+ * hash map
+ *
+ * time complexity: O(n)
+ * space complexity: O(n)
+ */
+var missingNumber = function (nums) {
+  const map = new Map();
+  for (let i = 0; i < nums.length; i++) {
+    map.set(nums[i], i);
+  }
+
+  for (let i = 0; i <= nums.length; i++) {
+    if (!map.has(i)) return i;
+  }
+};