Add MergeKSortedArrays algorithm (#5838)

src/test/java/com/thealgorithms/datastructures/heaps/MergeKSortedArraysTest.java

@@ -0,0 +1,41 @@
+package com.thealgorithms.datastructures.heaps;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+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;
+
+public class MergeKSortedArraysTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMergeKArrays(int[][] arrays, int[] expected) {
+        assertArrayEquals(expected, MergeKSortedArrays.mergeKArrays(arrays));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(
+            // Basic test case with multiple arrays
+            Arguments.of(new int[][] {{1, 4, 5}, {1, 3, 4}, {2, 6}}, new int[] {1, 1, 2, 3, 4, 4, 5, 6}),
+
+            // Edge case: All arrays are empty
+            Arguments.of(new int[][] {{}, {}, {}}, new int[] {}),
+
+            // Edge case: One array is empty
+            Arguments.of(new int[][] {{1, 3, 5}, {}, {2, 4, 6}}, new int[] {1, 2, 3, 4, 5, 6}),
+
+            // Single array
+            Arguments.of(new int[][] {{1, 2, 3}}, new int[] {1, 2, 3}),
+
+            // Arrays with negative numbers
+            Arguments.of(new int[][] {{-5, 1, 3}, {-10, 0, 2}}, new int[] {-10, -5, 0, 1, 2, 3}),
+
+            // Arrays with duplicate elements
+            Arguments.of(new int[][] {{1, 1, 2}, {1, 3, 3}, {2, 2, 4}}, new int[] {1, 1, 1, 2, 2, 2, 3, 3, 4}),
+
+            // Edge case: Arrays of varying lengths
+            Arguments.of(new int[][] {{1, 2}, {3}, {4, 5, 6, 7}}, new int[] {1, 2, 3, 4, 5, 6, 7}));
+    }
+}