Merge branch 'master' into dev3

Author: weilycoder

.gitignore

@@ -1,6 +1,7 @@
 config.py
 *.in
 *.out
+*.exe
 
 # Created by .ignore support plugin (hsz.mobi)
 ### Python template
@@ -131,4 +132,7 @@ docs/_build/
 target/
 
 # Pycharm
-venv
+venv
+
+# VS Code
+.vscode

cyaron/compare.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import, print_function
-from cyaron import IO, log
+from .io import IO
+from . import log
 from cyaron.utils import *
 from cyaron.consts import *
 from cyaron.graders import CYaRonGraders

cyaron/graph.py

@@ -304,7 +304,7 @@ def graph(point_count, edge_count, **kwargs):
     @staticmethod
     def DAG(point_count, edge_count, **kwargs):
         """DAG(point_count, edge_count, **kwargs) -> Graph
-               Factory method. Return a graph with point_count vertexes and edge_count edges.
+               Factory method. Return a directed connected graph with point_count vertexes and edge_count edges.
                int point_count -> the count of vertexes
                int edge_count -> the count of edges
                **kwargs(Keyword args):
@@ -371,7 +371,7 @@ def DAG(point_count, edge_count, **kwargs):
     @staticmethod
     def UDAG(point_count, edge_count, **kwargs):
         """UDAG(point_count, edge_count, **kwargs) -> Graph
-               Factory method. Return a graph with point_count vertexes and edge_count edges.
+               Factory method. Return a undirected connected graph with point_count vertexes and edge_count edges.
                int point_count -> the count of vertexes
                int edge_count -> the count of edges
                **kwargs(Keyword args):
@@ -426,6 +426,18 @@ def UDAG(point_count, edge_count, **kwargs):
             i += 1
 
         return graph
+    
+    @staticmethod
+    def connected(point_count, edge_count, directed=False, **kwargs):
+        """connected(point_count, edge_count, **kwargs) -> Graph
+           Factory method. Return a connected graph with point_count vertexes
+           int point_count -> the count of vertexes
+           bool directed -> whether the graph is directed
+        """
+        if directed:
+            return Graph.DAG(point_count, edge_count, **kwargs)
+        else:
+            return Graph.UDAG(point_count, edge_count, **kwargs)
 
     @staticmethod
     def hack_spfa(point_count, **kwargs):