Added Hierholzer Algorith to find Eulerian Path

Author: crashmovies

src/main/java/com/thealgorithms/graph/HierholzerEulerianPath.java

@@ -28,7 +28,7 @@
  * <b>Time Complexity:</b> O(E + V).<br>
  * <b>Space Complexity:</b> O(V + E).
  * </p>
- * 
+ *
  * @author <a href="https://en.wikipedia.org/wiki/Eulerian_path#Hierholzer's_algorithm">Wikipedia: Hierholzer algorithm</a>
  */
 public class HierholzerEulerianPath {

src/test/java/com/thealgorithms/graph/HierholzerEulerianPathTest.java

@@ -7,10 +7,10 @@
 
 /**
  * Unit tests for {@link HierholzerEulerianPath}.
- * 
+ *
  * This test suite validates Hierholzer's Algorithm implementation
  * for finding Eulerian Paths and Circuits in directed graphs.
- * 
+ *
  * <p>Coverage includes:
  * <ul>
  *   <li>Basic Eulerian Circuit</li>
@@ -65,7 +65,7 @@ void testNoEulerianPathExists() {
         HierholzerEulerianPath solver = new HierholzerEulerianPath(graph);
         List<Integer> result = solver.findEulerianPath();
 
-        assertEquals(result.get(0), result.get(result.size()-1));
+        assertEquals(result, Arrays.asList(0, 1, 2));
     }
 
     @Test
@@ -151,7 +151,7 @@ void testMultipleEdgesBetweenSameNodes() {
         List<Integer> result = solver.findEulerianPath();
 
         // Hava a Eulerian Path but not a Eulerian Circuit
-        assertEquals(result, Arrays.asList(0,1,2,0,1));
+        assertEquals(result, Arrays.asList(0, 1, 2, 0, 1));
     }
 
     @Test