Fix Dijkstra's Algorithm by exiting early at target vertex

src/common/WeightedEdgeGraph.cpp

@@ -62,9 +62,13 @@ int WeightedEdgeGraph::dijkstra(const int source, const int target) const
                 distances[neighbor] = newDistance;
                 queue.push(neighbor);
             }
+            if (neighbor == target)
+            {
+                return distances[target];
+            }
             incidence = vertexEdgeIncidences_[incidence].next;
         }
     }
 
-    return distances[target];
+    return -1;
 }