Adjust & add solution for ContainsDuplicates task

andrei-punko · andrei-punko · commit 3dacfb1595a9 · 2024-06-04T08:43:04.000+03:00
diff --git a/src/main/java/by/andd3dfx/collections/ContainsDuplicates.java b/src/main/java/by/andd3dfx/collections/ContainsDuplicates.java
@@ -28,7 +28,7 @@
  */
 public class ContainsDuplicates {
 
-    public boolean containsDuplicate(int[] nums) {
+    public boolean usingSet(int[] nums) {
         Set<Integer> set = new HashSet<>();
         for (int num : nums) {
             if (!set.add(num)) {
@@ -37,4 +37,28 @@ public boolean containsDuplicate(int[] nums) {
         }
         return false;
     }
+
+    public boolean usingSortWithEarlyReturn(int[] nums) {
+        for (int i = 0; i < nums.length; i++) {
+            int min_index = i;
+
+            for (int j = i + 1; j < nums.length; j++) {
+                if (nums[j] == nums[min_index]) {
+                    return true;
+                }
+                if (nums[j] < nums[min_index]) {
+                    min_index = j;
+                }
+            }
+
+            swap(nums, i, min_index);
+        }
+        return false;
+    }
+
+    private void swap(int[] array, int i, int j) {
+        var tmp = array[i];
+        array[i] = array[j];
+        array[j] = tmp;
+    }
 }
diff --git a/src/test/java/by/andd3dfx/collections/ContainsDuplicatesTest.java b/src/test/java/by/andd3dfx/collections/ContainsDuplicatesTest.java
@@ -16,9 +16,16 @@ public void setUp() throws Exception {
     }
 
     @Test
-    public void containsDuplicate() {
-        assertTrue(containsDuplicates.containsDuplicate(new int[]{1, 2, 3, 1}));
-        assertFalse(containsDuplicates.containsDuplicate(new int[]{1, 2, 3, 4}));
-        assertTrue(containsDuplicates.containsDuplicate(new int[]{1, 1, 1, 3, 3, 4, 3, 2, 4, 2}));
+    public void usingSet() {
+        assertTrue(containsDuplicates.usingSet(new int[]{2, 1, 3, 1}));
+        assertFalse(containsDuplicates.usingSet(new int[]{2, 1, 3, 56, 4}));
+        assertTrue(containsDuplicates.usingSet(new int[]{1, 1, 1, 3, 3, 4, 3, 2, 4, 2}));
+    }
+
+    @Test
+    public void usingSortWithEarlyReturn() {
+        assertTrue(containsDuplicates.usingSortWithEarlyReturn(new int[]{2, 1, 3, 1}));
+        assertFalse(containsDuplicates.usingSortWithEarlyReturn(new int[]{2, 1, 3, 56, 4}));
+        assertTrue(containsDuplicates.usingSortWithEarlyReturn(new int[]{1, 1, 1, 3, 3, 4, 3, 2, 4, 2}));
     }
 }
