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clean up graph search #152

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Merged
merged 2 commits into from
Aug 23, 2016
Merged

clean up graph search #152

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935d42f
clean up graph search
Xuefeng-Zhu Aug 22, 2016
b649a6a
fix minor issue
Xuefeng-Zhu Aug 22, 2016
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58 changes: 22 additions & 36 deletions graph_search.py
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Original file line number Diff line number Diff line change
Expand Up @@ -11,53 +11,39 @@ def __init__(self, graph):
self.graph = graph

def find_path(self, start, end, path=None):
self.start = start
self.end = end
self.path = path if path else []
path = path or []

self.path += [self.start]
if self.start == self.end:
return self.path
if self.start not in self.graph:
return None
for node in self.graph[self.start]:
if node not in self.path:
newpath = self.find_path(node, self.end, self.path)
path.append(start)
if start == end:
return path
for node in self.graph.get(start, []):
if node not in path:
newpath = self.find_path(node, end, path)
if newpath:
return newpath
return None

def find_all_path(self, start, end, path=None):
self.start = start
self.end = end
_path = path if path else []
_path += [self.start]
if self.start == self.end:
return [_path]
if self.start not in self.graph:
return []
path = path or []
path.append(start)
if start == end:
return [path]
paths = []
for node in self.graph[self.start]:
if node not in _path:
newpaths = self.find_all_path(node, self.end, _path[:])
for newpath in newpaths:
paths.append(newpath)
for node in self.graph.get(start, []):
if node not in path:
newpaths = self.find_all_path(node, end, path[:])
paths.extend(newpaths)
return paths

def find_shortest_path(self, start, end, path=None):
self.start = start
self.end = end
_path = path if path else []
path = path or []
path.append(start)

_path += [self.start]
if self.start == self.end:
return _path
if self.start not in self.graph:
return None
if start == end:
return path
shortest = None
for node in self.graph[self.start]:
if node not in _path:
newpath = self.find_shortest_path(node, self.end, _path[:])
for node in self.graph.get(start, []):
if node not in path:
newpath = self.find_shortest_path(node, end, path[:])
if newpath:
if not shortest or len(newpath) < len(shortest):
shortest = newpath
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