Create find-all-numbers-disappeared-in-an-array.cpp

Author: kamyu104

C++/find-all-numbers-disappeared-in-an-array.cpp

@@ -0,0 +1,23 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    vector<int> findDisappearedNumbers(vector<int>& nums) {
+        for (int i = 0; i < nums.size(); ++i) {
+            if (nums[abs(nums[i]) - 1] > 0) {
+                nums[abs(nums[i]) - 1] *= -1;
+            }
+        }
+
+        vector<int> result;
+        for (int i = 0; i < nums.size(); ++i) {
+            if (nums[i] > 0) {
+                result.emplace_back(i + 1);
+            } else {
+                nums[i] *= -1;
+            }
+        }
+        return result;
+    }
+};