Merge branch 'master' into 6438/ImprovementForHammingDistance

Author: DenizAltunkapan

src/test/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedListTest.java

@@ -90,4 +90,88 @@ private int[] getListValues(Node head) {
         }
         return Arrays.copyOf(values, i); // return only filled part
     }
+
+    @Test
+    void testMergeWithNullListsInArray() {
+        Node list1 = new Node(1, new Node(3));
+        Node list2 = null;
+        Node list3 = new Node(2, new Node(4));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3, 4};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle null lists mixed with valid lists");
+    }
+
+    @Test
+    void testMergeWithDuplicateValues() {
+        Node list1 = new Node(1, new Node(1, new Node(3)));
+        Node list2 = new Node(1, new Node(2, new Node(3)));
+        Node list3 = new Node(3, new Node(3));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 1, 1, 2, 3, 3, 3, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle duplicate values correctly");
+    }
+
+    @Test
+    void testMergeWithZeroLength() {
+        Node[] lists = {};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, 0);
+
+        assertNull(mergedHead, "Should return null for zero-length array");
+    }
+
+    @Test
+    void testMergeWithNegativeNumbers() {
+        Node list1 = new Node(-5, new Node(-1, new Node(3)));
+        Node list2 = new Node(-3, new Node(0, new Node(2)));
+        Node[] lists = {list1, list2};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {-5, -3, -1, 0, 2, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle negative numbers correctly");
+    }
+
+    @Test
+    void testMergeIdenticalLists() {
+        Node list1 = new Node(1, new Node(2, new Node(3)));
+        Node list2 = new Node(1, new Node(2, new Node(3)));
+        Node list3 = new Node(1, new Node(2, new Node(3)));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 1, 1, 2, 2, 2, 3, 3, 3};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should merge identical lists correctly");
+    }
+
+    @Test
+    void testMergeAlreadySortedSequence() {
+        Node list1 = new Node(1, new Node(2));
+        Node list2 = new Node(3, new Node(4));
+        Node list3 = new Node(5, new Node(6));
+        Node[] lists = {list1, list2, list3};
+
+        MergeKSortedLinkedList merger = new MergeKSortedLinkedList();
+        Node mergedHead = merger.mergeKList(lists, lists.length);
+
+        int[] expectedValues = {1, 2, 3, 4, 5, 6};
+        int[] actualValues = getListValues(mergedHead);
+        assertArrayEquals(expectedValues, actualValues, "Should handle already sorted sequence");
+    }
 }

src/test/java/com/thealgorithms/others/CRCAlgorithmTest.java

@@ -79,4 +79,85 @@ void testLargeMessageSize() {
         assertTrue(c.getWrongMess() >= 0);
         assertTrue(c.getCorrectMess() >= 0);
     }
+
+    @Test
+    void testSingleBitMessage() {
+        CRCAlgorithm c = new CRCAlgorithm("11", 1, 0.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        assertTrue(c.getCorrectMess() >= 0, "Single bit message should be handled");
+    }
+
+    @Test
+    void testPolynomialLongerThanMessage() {
+        CRCAlgorithm c = new CRCAlgorithm("11010101", 3, 0.0);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        // Should not crash, counters should be valid
+        assertTrue(c.getCorrectMess() + c.getWrongMess() >= 0);
+    }
+
+    @Test
+    void testPolynomialWithOnlyOnes() {
+        CRCAlgorithm c = new CRCAlgorithm("1111", 5, 0.1);
+        c.generateRandomMess();
+        c.divideMessageWithP(false);
+        c.changeMess();
+        c.divideMessageWithP(true);
+
+        assertTrue(c.getCorrectMess() + c.getWrongMess() >= 0);
+    }
+
+    @Test
+    void testMultipleRefactorCalls() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 5, 0.2);
+
+        for (int i = 0; i < 5; i++) {
+            c.refactor();
+            c.generateRandomMess();
+            c.divideMessageWithP(false);
+            c.changeMess();
+            c.divideMessageWithP(true);
+        }
+
+        // Counters should accumulate across multiple runs
+        assertTrue(c.getCorrectMess() + c.getWrongMess() > 0);
+    }
+
+    @Test
+    void testCounterConsistency() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 10, 0.3);
+
+        for (int i = 0; i < 100; i++) {
+            c.refactor();
+            c.generateRandomMess();
+            c.divideMessageWithP(false);
+            c.changeMess();
+            c.divideMessageWithP(true);
+        }
+
+        // Total messages processed should equal correct + wrong
+        int totalProcessed = c.getCorrectMess() + c.getWrongMess();
+        assertEquals(100, totalProcessed, "Total processed messages should equal iterations");
+
+        // Wrong messages should equal caught + not caught
+        assertEquals(c.getWrongMess(), c.getWrongMessCaught() + c.getWrongMessNotCaught(), "Wrong messages should equal sum of caught and not caught");
+    }
+
+    @Test
+    void testGetterMethodsInitialState() {
+        CRCAlgorithm c = new CRCAlgorithm("1101", 10, 0.1);
+
+        // Check initial state
+        assertEquals(0, c.getCorrectMess(), "Initial correct messages should be 0");
+        assertEquals(0, c.getWrongMess(), "Initial wrong messages should be 0");
+        assertEquals(0, c.getWrongMessCaught(), "Initial caught wrong messages should be 0");
+        assertEquals(0, c.getWrongMessNotCaught(), "Initial not caught wrong messages should be 0");
+    }
 }