Merge branch 'master' into testing/DisjointSetUnionTest

Author: DenizAltunkapan

src/test/java/com/thealgorithms/datastructures/bag/BagTest.java

@@ -6,7 +6,10 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.thealgorithms.datastructures.bags.Bag;
+import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
 import org.junit.jupiter.api.Test;
 
 class BagTest {
@@ -156,4 +159,116 @@ void testIteratorWithDuplicates() {
         }
         assertEquals(3, count, "Iterator should traverse all 3 items including duplicates");
     }
+
+    @Test
+    void testCollectionElements() {
+        Bag<List<String>> bag = new Bag<>();
+        List<String> list1 = new ArrayList<>();
+        list1.add("a");
+        list1.add("b");
+
+        List<String> list2 = new ArrayList<>();
+        list2.add("c");
+
+        List<String> emptyList = new ArrayList<>();
+
+        bag.add(list1);
+        bag.add(list2);
+        bag.add(emptyList);
+        bag.add(list1); // Duplicate
+
+        assertEquals(4, bag.size(), "Bag should contain 4 list elements");
+        assertTrue(bag.contains(list1), "Bag should contain list1");
+        assertTrue(bag.contains(list2), "Bag should contain list2");
+        assertTrue(bag.contains(emptyList), "Bag should contain empty list");
+    }
+
+    @Test
+    void testIteratorConsistency() {
+        Bag<String> bag = new Bag<>();
+        bag.add("first");
+        bag.add("second");
+        bag.add("third");
+
+        // Multiple iterations should return same elements
+        List<String> firstIteration = new ArrayList<>();
+        for (String item : bag) {
+            firstIteration.add(item);
+        }
+
+        List<String> secondIteration = new ArrayList<>();
+        for (String item : bag) {
+            secondIteration.add(item);
+        }
+
+        assertEquals(firstIteration.size(), secondIteration.size(), "Both iterations should have same size");
+        assertEquals(3, firstIteration.size(), "First iteration should have 3 elements");
+        assertEquals(3, secondIteration.size(), "Second iteration should have 3 elements");
+    }
+
+    @Test
+    void testMultipleIterators() {
+        Bag<String> bag = new Bag<>();
+        bag.add("item1");
+        bag.add("item2");
+
+        Iterator<String> iter1 = bag.iterator();
+        Iterator<String> iter2 = bag.iterator();
+
+        assertTrue(iter1.hasNext(), "First iterator should have next element");
+        assertTrue(iter2.hasNext(), "Second iterator should have next element");
+
+        String first1 = iter1.next();
+        String first2 = iter2.next();
+
+        org.junit.jupiter.api.Assertions.assertNotNull(first1, "First iterator should return non-null element");
+        org.junit.jupiter.api.Assertions.assertNotNull(first2, "Second iterator should return non-null element");
+    }
+
+    @Test
+    void testIteratorHasNextConsistency() {
+        Bag<String> bag = new Bag<>();
+        bag.add("single");
+
+        Iterator<String> iter = bag.iterator();
+        assertTrue(iter.hasNext(), "hasNext should return true");
+        assertTrue(iter.hasNext(), "hasNext should still return true after multiple calls");
+
+        String item = iter.next();
+        assertEquals("single", item, "Next should return the single item");
+
+        assertFalse(iter.hasNext(), "hasNext should return false after consuming element");
+        assertFalse(iter.hasNext(), "hasNext should still return false");
+    }
+
+    @Test
+    void testIteratorNextOnEmptyBag() {
+        Bag<String> bag = new Bag<>();
+        Iterator<String> iter = bag.iterator();
+
+        assertFalse(iter.hasNext(), "hasNext should return false for empty bag");
+        assertThrows(NoSuchElementException.class, iter::next, "next() should throw NoSuchElementException on empty bag");
+    }
+
+    @Test
+    void testBagOrderIndependence() {
+        Bag<String> bag1 = new Bag<>();
+        Bag<String> bag2 = new Bag<>();
+
+        // Add same elements in different order
+        bag1.add("first");
+        bag1.add("second");
+        bag1.add("third");
+
+        bag2.add("third");
+        bag2.add("first");
+        bag2.add("second");
+
+        assertEquals(bag1.size(), bag2.size(), "Bags should have same size");
+
+        // Both bags should contain all elements
+        assertTrue(bag1.contains("first") && bag2.contains("first"));
+        assertTrue(bag1.contains("second") && bag2.contains("second"));
+        assertTrue(bag1.contains("third") && bag2.contains("third"));
+    }
 }

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

@@ -109,4 +109,189 @@ void testMemoryLimitExceeded() {
             }
         });
     }
+
+    @Test
+    void testSingleElementOperations() {
+        // Test operations with just one element
+        list.append("Only");
+        assertEquals("Only", list.get(0));
+        assertEquals(0, list.indexOf("Only"));
+
+        list.remove("Only");
+        assertNull(list.get(0));
+        assertEquals(-1, list.indexOf("Only"));
+    }
+
+    @Test
+    void testDuplicateElements() {
+        // Test handling of duplicate elements
+        list.append("Duplicate");
+        list.append("Other");
+        list.append("Duplicate");
+
+        assertEquals(0, list.indexOf("Duplicate")); // Should return first occurrence
+        assertEquals("Duplicate", list.get(0));
+        assertEquals("Duplicate", list.get(2));
+
+        list.remove("Duplicate"); // Should remove first occurrence
+        assertEquals("Other", list.get(0));
+        assertEquals("Duplicate", list.get(1));
+    }
+
+    @Test
+    void testRemoveByIndexEdgeCases() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        // Test removing invalid indices
+        list.removeByIndex(-1); // Should not crash
+        list.removeByIndex(10); // Should not crash
+
+        // Verify list unchanged
+        assertEquals("First", list.get(0));
+        assertEquals("Second", list.get(1));
+        assertEquals("Third", list.get(2));
+
+        // Test removing first element by index
+        list.removeByIndex(0);
+        assertEquals("Second", list.get(0));
+        assertEquals("Third", list.get(1));
+    }
+
+    @Test
+    void testRemoveByIndexLastElement() {
+        list.append("First");
+        list.append("Second");
+        list.append("Third");
+
+        // Remove last element by index
+        list.removeByIndex(2);
+        assertEquals("First", list.get(0));
+        assertEquals("Second", list.get(1));
+        assertNull(list.get(2));
+    }
+
+    @Test
+    void testConsecutiveOperations() {
+        // Test multiple consecutive operations
+        list.append("A");
+        list.append("B");
+        list.append("C");
+        list.append("D");
+
+        list.remove("B");
+        list.remove("D");
+
+        assertEquals("A", list.get(0));
+        assertEquals("C", list.get(1));
+        assertNull(list.get(2));
+
+        list.append("E");
+        assertEquals("E", list.get(2));
+    }
+
+    @Test
+    void testMemoryReclamation() {
+        // Test that removed elements free up memory space
+        for (int i = 0; i < 50; i++) {
+            list.append("Element" + i);
+        }
+
+        // Remove some elements
+        for (int i = 0; i < 25; i++) {
+            list.remove("Element" + i);
+        }
+
+        // Should be able to add more elements (testing memory reclamation)
+        for (int i = 100; i < 150; i++) {
+            list.append("New" + i);
+        }
+
+        // Verify some elements exist
+        assertEquals("Element25", list.get(0));
+        assertEquals("New100", list.get(25));
+    }
+
+    @Test
+    void testSpecialCharacters() {
+        // Test with strings containing special characters
+        list.append("Hello World!");
+        list.append("Test@123");
+        list.append("Special#$%");
+        list.append(""); // Empty string
+
+        assertEquals("Hello World!", list.get(0));
+        assertEquals("Test@123", list.get(1));
+        assertEquals("Special#$%", list.get(2));
+        assertEquals("", list.get(3));
+
+        assertEquals(3, list.indexOf(""));
+    }
+
+    @Test
+    void testLargeIndices() {
+        list.append("Test");
+
+        // Test very large indices
+        assertNull(list.get(Integer.MAX_VALUE));
+        assertNull(list.get(1000));
+    }
+
+    @Test
+    void testSequentialRemovalByIndex() {
+        list.append("A");
+        list.append("B");
+        list.append("C");
+        list.append("D");
+
+        // Remove elements sequentially by index
+        list.removeByIndex(1); // Remove "B"
+        assertEquals("A", list.get(0));
+        assertEquals("C", list.get(1));
+        assertEquals("D", list.get(2));
+
+        list.removeByIndex(1); // Remove "C"
+        assertEquals("A", list.get(0));
+        assertEquals("D", list.get(1));
+        assertNull(list.get(2));
+    }
+
+    @Test
+    void testAppendAfterRemoval() {
+        list.append("First");
+        list.append("Second");
+
+        list.remove("First");
+        list.append("Third");
+
+        assertEquals("Second", list.get(0));
+        assertEquals("Third", list.get(1));
+        assertEquals(1, list.indexOf("Third"));
+    }
+
+    @Test
+    void testPerformanceWithManyOperations() {
+        // Test with many mixed operations
+        for (int i = 0; i < 50; i++) {
+            list.append("Item" + i);
+        }
+
+        // Remove every other element
+        for (int i = 0; i < 50; i += 2) {
+            list.remove("Item" + i);
+        }
+
+        // Verify remaining elements
+        assertEquals("Item1", list.get(0));
+        assertEquals("Item3", list.get(1));
+        assertEquals("Item5", list.get(2));
+
+        // Add more elements
+        for (int i = 100; i < 110; i++) {
+            list.append("New" + i);
+        }
+
+        assertEquals("New100", list.get(25));
+    }
 }

src/test/java/com/thealgorithms/datastructures/queues/DequeTest.java

@@ -121,4 +121,77 @@ void testNullValues() {
         assertNull(deque.pollFirst());
         org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty());
     }
+
+    @Test
+    void testMultipleAddFirst() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(1);
+        deque.addFirst(2);
+        deque.addFirst(3);
+
+        assertEquals(3, deque.peekFirst(), "First element should be the last added to front");
+        assertEquals(1, deque.peekLast(), "Last element should be the first added to front");
+        assertEquals(3, deque.size(), "Size should reflect all additions");
+    }
+
+    @Test
+    void testMultipleAddLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addLast(1);
+        deque.addLast(2);
+        deque.addLast(3);
+
+        assertEquals(1, deque.peekFirst(), "First element should be the first added to back");
+        assertEquals(3, deque.peekLast(), "Last element should be the last added to back");
+        assertEquals(3, deque.size(), "Size should reflect all additions");
+    }
+
+    @Test
+    void testSingleElementOperations() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addFirst(1);
+
+        assertEquals(1, deque.peekFirst(), "Single element should be both first and last");
+        assertEquals(1, deque.peekLast(), "Single element should be both first and last");
+        assertEquals(1, deque.size());
+
+        assertEquals(1, deque.pollFirst(), "Should be able to poll single element from front");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after polling single element");
+    }
+
+    @Test
+    void testSingleElementPollLast() {
+        Deque<Integer> deque = new Deque<>();
+        deque.addLast(1);
+
+        assertEquals(1, deque.pollLast(), "Should be able to poll single element from back");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after polling single element");
+    }
+
+    @Test
+    void testMixedNullAndValues() {
+        Deque<String> deque = new Deque<>();
+        deque.addFirst("first");
+        deque.addLast(null);
+        deque.addFirst(null);
+        deque.addLast("last");
+
+        assertEquals(4, deque.size(), "Should handle mixed null and non-null values");
+        assertNull(deque.pollFirst(), "Should poll null from front");
+        assertEquals("first", deque.pollFirst(), "Should poll non-null value");
+        assertNull(deque.pollLast().equals("last") ? null : deque.peekLast(), "Should handle null correctly");
+    }
+
+    @Test
+    void testSymmetricOperations() {
+        Deque<Integer> deque = new Deque<>();
+
+        // Test that addFirst/pollFirst and addLast/pollLast are symmetric
+        deque.addFirst(1);
+        deque.addLast(2);
+
+        assertEquals(1, deque.pollFirst(), "addFirst/pollFirst should be symmetric");
+        assertEquals(2, deque.pollLast(), "addLast/pollLast should be symmetric");
+        org.junit.jupiter.api.Assertions.assertTrue(deque.isEmpty(), "Deque should be empty after symmetric operations");
+    }
 }