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* Retranslate the complete English edition from Simplified Chinese * Polish three English explanations after reader-focused review
62 lines
1.6 KiB
Ruby
62 lines
1.6 KiB
Ruby
=begin
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File: graph_bfs.rb
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Created Time: 2024-04-25
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Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
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=end
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require 'set'
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require_relative './graph_adjacency_list'
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require_relative '../utils/vertex'
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### Breadth-first traversal ###
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def graph_bfs(graph, start_vet)
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# Represent the graph with an adjacency list to access all neighbors of a given vertex
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# Vertex traversal sequence
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res = []
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# Hash set recording visited vertices
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visited = Set.new([start_vet])
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# Use a queue to implement BFS
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que = [start_vet]
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# Start from start_vet and loop until all reachable vertices have been visited
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while que.length > 0
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vet = que.shift # Dequeue the front vertex
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res << vet # Record the visited vertex
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# Traverse all neighbors of this vertex
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for adj_vet in graph.adj_list[vet]
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next if visited.include?(adj_vet) # Skip vertices that have already been visited
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que << adj_vet # Enqueue only unvisited vertices
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visited.add(adj_vet) # Mark this vertex as visited
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end
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end
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# Return the vertex traversal sequence
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res
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end
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### Driver code ###
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if __FILE__ == $0
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# Initialize the undirected graph
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v = vals_to_vets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
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edges = [
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[v[0], v[1]],
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[v[0], v[3]],
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[v[1], v[2]],
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[v[1], v[4]],
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[v[2], v[5]],
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[v[3], v[4]],
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[v[3], v[6]],
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[v[4], v[5]],
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[v[4], v[7]],
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[v[5], v[8]],
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[v[6], v[7]],
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[v[7], v[8]],
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]
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graph = GraphAdjList.new(edges)
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puts "\nGraph after initialization:"
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graph.__print__
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# Breadth-first traversal
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res = graph_bfs(graph, v.first)
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puts "\nBreadth-first traversal (BFS) vertex sequence:"
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p vets_to_vals(res)
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end
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