Merge branch 'develop' into beta

Author: justcoding121

src/Advanced.Algorithms/Graph/Matching/HopcroftKarp.cs

@@ -43,20 +43,20 @@ private HashSet<MatchEdge<T>> getMaxBiPartiteMatching(IGraph<T> graph,
             while (freeVerticesOnRight.Count > 0)
             {
                 var visited = new HashSet<T>();
-                var paths = new HashSet<MatchEdge<T>>();
+                var path = new HashSet<MatchEdge<T>>();
 
                 foreach (var vertex in freeVerticesOnRight)
                 {
-                    var path = dfs(graph,
+                    var currentPath = dfs(graph,
                       leftToRightMatchEdges, rightToLeftMatchEdges, vertex, default, visited, true);
 
-                    if (path != null)
+                    if (currentPath != null)
                     {
-                        union(paths, path);
+                        union(path, currentPath);
                     }
                 }
 
-                xor(matches, paths, leftToRightMatchEdges, rightToLeftMatchEdges);
+                xor(matches, path, leftToRightMatchEdges, rightToLeftMatchEdges);
 
                 freeVerticesOnRight = bfs(graph, partitions, leftToRightMatchEdges, rightToLeftMatchEdges);
             }
@@ -81,14 +81,14 @@ private List<T> bfs(IGraph<T> graph,
             foreach (var vertex in partitions[1])
             {
                 //if this left vertex is free
-                if (!leftToRightMatchEdges.ContainsKey(vertex))
+                if (!leftToRightMatchEdges.ContainsKey(vertex) && !visited.Contains(vertex))
                 {
                     queue.Enqueue(vertex);
-                    visited.Add(vertex);
-
+                    
                     while (queue.Count > 0)
                     {
                         var current = queue.Dequeue();
+                        visited.Add(vertex);
 
                         //unmatched edges left to right
                         foreach (var leftToRightEdge in graph.GetVertex(current).Edges)