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47 lines
1.5 KiB
Python
47 lines
1.5 KiB
Python
"""
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File: graph_dfs.py
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Created Time: 2023-02-23
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Author: Krahets (krahets@163.com)
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"""
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import sys, os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from modules import *
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from graph_adjacency_list import GraphAdjList
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def dfs(graph: GraphAdjList, visited: set[Vertex], res: list[Vertex], vet: Vertex):
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""" 深度优先遍历 DFS 辅助函数 """
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res.append(vet) # 记录访问顶点
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visited.add(vet) # 标记该顶点已被访问
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# 遍历该顶点的所有邻接顶点
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for adjVet in graph.adj_list[vet]:
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if adjVet in visited:
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continue # 跳过已被访问过的顶点
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# 递归访问邻接顶点
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dfs(graph, visited, res, adjVet)
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# 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
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def graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
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""" 深度优先遍历 DFS """
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# 顶点遍历序列
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res = []
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# 哈希表，用于记录已被访问过的顶点
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visited = set[Vertex]()
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dfs(graph, visited, res, start_vet)
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return res
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""" Driver Code """
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if __name__ == "__main__":
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# 初始化无向图
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v = vals_to_vets([0, 1, 2, 3, 4, 5, 6])
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edges = [[v[0], v[1]], [v[0], v[3]], [v[1], v[2]],
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[v[2], v[5]], [v[4], v[5]], [v[5], v[6]]]
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graph = GraphAdjList(edges)
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print("\n初始化后，图为")
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graph.print()
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# 深度优先遍历 DFS
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res = graph_dfs(graph, v[0])
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print("\n深度优先遍历（DFS）顶点序列为")
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print(vets_to_vals(res))
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