fix mistake usage of self param in recursive func and [] as default param

nick-jiang · nick-jiang · commit 6eb5e6283dc7 · 2014-08-16T23:44:24.000+08:00
diff --git a/graph_search.py b/graph_search.py
@@ -10,10 +10,10 @@ class GraphSearch:
 def __init__(self, graph):
 self.graph = graph
 
- def find_path(self, start, end, path=[]):
+ def find_path(self, start, end, path=None):
 self.start = start
 self.end = end
- self.path = path
+ self.path = path if path else []
 
 self.path += [self.start]
 if self.start == self.end:
@@ -27,37 +27,37 @@ def find_path(self, start, end, path=[]):
 return newpath
 return None
 
- def find_all_path(self, start, end, path=[]):
+ def find_all_path(self, start, end, path=None):
 self.start = start
 self.end = end
- self.path = path
- self.path += [self.start]
+ _path = path if path else []
+ _path += [self.start]
 if self.start == self.end:
- return [self.path]
+ return [_path]
 if self.start not in self.graph:
 return []
 paths = []
 for node in self.graph[self.start]:
- if node not in self.path:
- newpaths = self.find_all_path(node, self.end, self.path)
+ if node not in _path:
+ newpaths = self.find_all_path(node, self.end, _path[:])
 for newpath in newpaths:
 paths.append(newpath)
 return paths
 
- def find_shortest_path(self, start, end, path=[]):
+ def find_shortest_path(self, start, end, path=None):
 self.start = start
 self.end = end
- self.path = path
+ _path = path if path else []
 
- self.path += [self.start]
+ _path += [self.start]
 if self.start == self.end:
- return self.path
+ return _path
 if self.start not in self.graph:
 return None
 shortest = None
 for node in self.graph[self.start]:
- if node not in self.path:
- newpath = self.find_shortest_path(node, self.end, self.path)
+ if node not in _path:
+ newpath = self.find_shortest_path(node, self.end, _path[:])
 if newpath:
 if not shortest or len(newpath) < len(shortest):
 shortest = newpath
@@ -82,5 +82,5 @@ def find_shortest_path(self, start, end, path=[]):
 
 ### OUTPUT ###
 # ['A', 'B', 'C', 'D']
-# [['A', 'B', 'C', 'D']]
-# ['A', 'B', 'C', 'D']
+# [['A', 'B', 'C', 'D'], ['A', 'B', 'D'], ['A', 'C', 'D']]
+# ['A', 'B', 'D']

-Original file line number
+Diff line change
 def__init__(self, graph):
 self.graph=graph
 -deffind_path(self, start, end, path=[]):
 +deffind_path(self, start, end, path=None):
 self.start=start
 self.end=end
 -self.path=path
 +self.path=pathifpathelse []
 self.path+= [self.start]
 ifself.start==self.end:
 returnnewpath
 returnNone
 -deffind_all_path(self, start, end, path=[]):
 +deffind_all_path(self, start, end, path=None):
 self.start=start
 self.end=end
 -self.path=path
 -self.path+= [self.start]
 +_path=pathifpathelse []
 +_path+= [self.start]
 ifself.start==self.end:
 -return [self.path]
 +return [_path]
 ifself.startnotinself.graph:
 return []
 paths= []
 fornodeinself.graph[self.start]:
 -ifnodenotinself.path:
 -newpaths=self.find_all_path(node, self.end, self.path)
 +ifnodenotin_path:
 +newpaths=self.find_all_path(node, self.end, _path[:])
 fornewpathinnewpaths:
 paths.append(newpath)
 returnpaths
 -deffind_shortest_path(self, start, end, path=[]):
 +deffind_shortest_path(self, start, end, path=None):
 self.start=start
 self.end=end
 -self.path=path
 +_path=pathifpathelse []
 -self.path+= [self.start]
 +_path+= [self.start]
 ifself.start==self.end:
 -returnself.path
 +return_path
 ifself.startnotinself.graph:
 returnNone
 shortest=None
 fornodeinself.graph[self.start]:
 -ifnodenotinself.path:
 -newpath=self.find_shortest_path(node, self.end, self.path)
 +ifnodenotin_path:
 +newpath=self.find_shortest_path(node, self.end, _path[:])
 ifnewpath:
 ifnotshortestorlen(newpath) <len(shortest):
 shortest=newpath
 ### OUTPUT ###
 # ['A', 'B', 'C', 'D']
 -# [['A', 'B', 'C', 'D']]
 -# ['A', 'B', 'C', 'D']
 +# [['A', 'B', 'C', 'D'], ['A', 'B', 'D'], ['A', 'C', 'D']]
 +# ['A', 'B', 'D']