=begin File: graph_bfs.rb Created Time: 2024-04-25 Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com) =end require 'set' require_relative './graph_adjacency_list' require_relative '../utils/vertex' ### 广度优先遍历 ### def graph_bfs(graph, start_vet) # 使用邻接表来表示图,以便获取指定顶点的所有邻接顶点 # 顶点遍历序列 res = [] # 哈希表,用于记录已被访问过的顶点 visited = Set.new([start_vet]) # 队列用于实现 BFS que = [start_vet] # 以顶点 vet 为起点,循环直至访问完所有顶点 while que.length > 0 vet = que.shift # 队首顶点出队 res << vet # 记录访问顶点 # 遍历该顶点的所有邻接顶点 for adj_vet in graph.adj_list[vet] next if visited.include?(adj_vet) # 跳过已被访问的顶点 que << adj_vet # 只入队未访问的顶点 visited.add(adj_vet) # 标记该顶点已被访问 end end # 返回顶点遍历序列 res end ### Driver Code ### if __FILE__ == $0 # 初始化无向图 v = vals_to_vets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) edges = [ [v[0], v[1]], [v[0], v[3]], [v[1], v[2]], [v[1], v[4]], [v[2], v[5]], [v[3], v[4]], [v[3], v[6]], [v[4], v[5]], [v[4], v[7]], [v[5], v[8]], [v[6], v[7]], [v[7], v[8]], ] graph = GraphAdjList.new(edges) puts "\n初始化后,图为" graph.__print__ # 广度优先遍历 res = graph_bfs(graph, v.first) puts "\n广度优先便利(BFS)顶点序列为" p vets_to_vals(res) end