本文实例讲述了python数据结构之图的实现方法。分享给大家供大家参考。具体如下:
下面简要的介绍下:
比如有这么一张图:
A -> B
A -> C
B -> C
B -> D
C -> D
D -> C
E -> F
F -> C
可以用字典和列表来构建
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graph = { 'A' : [ 'B' , 'C' ],
'B' : [ 'C' , 'D' ],
'C' : [ 'D' ],
'D' : [ 'C' ],
'E' : [ 'F' ],
'F' : [ 'C' ]}
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找到一条路径:
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def find_path(graph, start, end, path = []):
path = path + [start]
if start = = end:
return path
if not graph.has_key(start):
return None
for node in graph[start]:
if node not in path:
newpath = find_path(graph, node, end, path)
if newpath: return newpath
return None
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找到所有路径:
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def find_all_paths(graph, start, end, path = []):
path = path + [start]
if start = = end:
return [path]
if not graph.has_key(start):
return []
paths = []
for node in graph[start]:
if node not in path:
newpaths = find_all_paths(graph, node, end, path)
for newpath in newpaths:
paths.append(newpath)
return paths
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找到最短路径:
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def find_shortest_path(graph, start, end, path = []):
path = path + [start]
if start = = end:
return path
if not graph.has_key(start):
return None
shortest = None
for node in graph[start]:
if node not in path:
newpath = find_shortest_path(graph, node, end, path)
if newpath:
if not shortest or len (newpath) < len (shortest):
shortest = newpath
return shortest
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希望本文所述对大家的Python程序设计有所帮助。