Fix outdated refernce to connected components

Author: clue

src/Eulerian.php

@@ -12,14 +12,15 @@ class Eulerian extends BaseGraph
      * check whether this graph has an eulerian cycle
      *
      * @return boolean
-     * @uses Graph::isConnected()
+     * @uses ConnectedComponents::isSingle()
      * @uses Degree::getDegreeVertex()
      * @todo isolated vertices should be ignored
      * @todo definition is only valid for undirected graphs
      */
     public function hasCycle()
     {
-        if ($this->graph->isConnected()) {
+        $components = new ConnectedComponents($this->graph);
+        if ($components->isSingle()) {
             $alg = new Degree($this->graph);
 
             foreach ($this->graph->getVertices() as $vertex) {