Find All Duplicates in an Array

FindAllDuplicatesInAnArray.cpp

@@ -0,0 +1,33 @@
+class Solution {
+public:
+    void swap(int& a, int& b){
+        int temp = a;
+        a = b;
+        b = temp;
+    }
+
+    vector<int> findDuplicates(vector<int>& nums) {
+        int n = nums.size(), i = 0;
+
+        while(i < n){
+            while((nums[i]-1 != i) && (nums[i] != nums[nums[i]-1])){
+                swap(nums[i], nums[nums[i]-1]);
+            }
+            i++;
+        }
+
+        vector<int> ans;
+
+        for(int i = 0; i < n; i++){
+            if(nums[i]-1 != i){
+                ans.push_back(nums[i]);
+            }
+        }
+
+        if(ans.size()){
+            sort(ans.begin(), ans.end());
+        }
+
+        return ans;
+    }
+};