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  • python数据结构之图的实现方法

    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

    graph = {'A': ['B', 'C'],
           'B': ['C', 'D'],
           'C': ['D'],
           'D': ['C'],
           'E': ['F'],
           'F': ['C']}

    找到一条路径:

    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

    找到所有路径:

    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

    找到最短路径:

    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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  • 原文地址:https://www.cnblogs.com/ceo-python/p/11630989.html
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