Missing Number

Author: TonyKim9401

missing-number/TonyKim9401.java

@@ -0,0 +1,13 @@
+// TC: O(n log n)
+// SC: O(n)
+class Solution {
+    public int missingNumber(int[] nums) {
+        Arrays.sort(nums);
+        int idx = 1;
+        int n = nums.length;
+        for (; idx < n; idx++) {
+            if (nums[idx] - 1 != nums[idx-1]) return nums[idx] - 1;
+        }
+        return nums[idx-1] == n ? 0 : n;
+    }
+}