Enhance docs, add more tests in NumberAppearingOddTimes (#5857)

src/test/java/com/thealgorithms/bitmanipulation/NumberAppearingOddTimesTest.java

@@ -2,22 +2,48 @@ package com.thealgorithms.bitmanipulation;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 class NumberAppearingOddTimesTest {
 
-    @Test
-    void testFindOddOccurrence() {
-        int[] arr1 = {5, 6, 7, 8};
-        assertEquals(12, NumberAppearingOddTimes.findOddOccurrence(arr1));
+    /**
+     * Parameterized test for findOddOccurrence method. Tests multiple
+     * input arrays and their expected results.
+     */
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    void testFindOddOccurrence(int[] input, int expected) {
+        assertEquals(expected, NumberAppearingOddTimes.findOddOccurrence(input));
+    }
 
-        int[] arr2 = {2, 3, 5, 4, 5, 2, 4, 3, 5, 2, 4, 4, 2};
-        assertEquals(5, NumberAppearingOddTimes.findOddOccurrence(arr2));
+    /**
+     * Provides test cases for the parameterized test.
+     * Each test case consists of an input array and the expected result.
+     */
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Single element appearing odd times (basic case)
+            Arguments.of(new int[] {5, 6, 7, 8, 6, 7, 5}, 8),
 
-        int[] arr3 = {10, 10, 20, 20, 30};
-        assertEquals(30, NumberAppearingOddTimes.findOddOccurrence(arr3));
+            // More complex case with multiple pairs
+            Arguments.of(new int[] {2, 3, 5, 4, 5, 2, 4, 3, 5, 2, 4, 4, 2}, 5),
 
-        int[] arr4 = {-5, -5, -3, -3, -7, -7, -7};
-        assertEquals(-7, NumberAppearingOddTimes.findOddOccurrence(arr4));
+            // Case with only one element appearing once
+            Arguments.of(new int[] {10, 10, 20, 20, 30}, 30),
+
+            // Negative numbers with an odd occurrence
+            Arguments.of(new int[] {-5, -5, -3, -3, -7, -7, -7}, -7),
+
+            // All elements cancel out to 0 (even occurrences of all elements)
+            Arguments.of(new int[] {1, 2, 1, 2}, 0),
+
+            // Array with a single element (trivial case)
+            Arguments.of(new int[] {42}, 42),
+
+            // Large array with repeated patterns
+            Arguments.of(new int[] {1, 1, 2, 2, 3, 3, 3, 4, 4}, 3));
     }
 }