Create findAllDuplicates.java

LeetCode/findAllDuplicates.java

@@ -0,0 +1,33 @@
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class findAllDuplicates {
+    public static void main(String[] args) {
+        int[] arr = {1, 3, 2, 8, 4, 7, 6, 5, 4, 2, 8};
+        System.out.println(cycle(arr));
+    }
+
+    public static List<Integer> cycle(int[] arr) {
+        List<Integer> list = new ArrayList<>();
+        int i = 0;
+        while (i < arr.length) {
+            int correct = arr[i] - 1;
+            if (arr[i] != arr[correct]) {
+                swap(arr, i, correct);
+            } else i++;
+        }
+        for (int j = 0; j < arr.length; j++) {
+            if (arr[j] != j + 1) {
+                list.add(arr[j]);
+            }
+        }
+        return list;
+    }
+
+    public static void swap(int[] arr, int first, int second) {
+        int temp = arr[first];
+        arr[first] = arr[second];
+        arr[second] = temp;
+    }
+}