mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 08:46:28 +08:00
870e3e5cb2
* Sync zh and zh-hant versions * Update en/README.md * Add a Q&A for chapter of introduction * Update the callout headers * Sync zh ang zh-hant versions * Bug fixes
61 lines
1.5 KiB
Ruby
61 lines
1.5 KiB
Ruby
=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'
|
||
|
||
### 廣度優先走訪 ###
|
||
def graph_bfs(graph, start_vet)
|
||
# 使用鄰接表來表示圖，以便獲取指定頂點的所有鄰接頂點
|
||
# 頂點走訪序列
|
||
res = []
|
||
# 雜湊集合，用於記錄已被訪問過的頂點
|
||
visited = Set.new([start_vet])
|
||
# 佇列用於實現 BFS
|
||
que = [start_vet]
|
||
# 以頂點 vet 為起點，迴圈直至訪問完所有頂點
|
||
while que.length > 0
|
||
vet = que.shift # 佇列首頂點出隊
|
||
res << vet # 記錄訪問頂點
|
||
# 走訪該頂點的所有鄰接頂點
|
||
for adj_vet in graph.adj_list[vet]
|
||
next if visited.include?(adj_vet) # 跳過已被訪問的頂點
|
||
que << adj_vet # 只入列未訪問的頂點
|
||
visited.add(adj_vet) # 標記該頂點已被訪問
|
||
end
|
||
end
|
||
# 返回頂點走訪序列
|
||
res
|
||
end
|
||
|
||
### Driver Code ###
|
||
if __FILE__ == $0
|
||
# 初始化無向圖
|
||
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初始化後，圖為"
|
||
graph.__print__
|
||
|
||
# 廣度優先走訪
|
||
res = graph_bfs(graph, v.first)
|
||
puts "\n廣度優先便利（BFS）頂點序列為"
|
||
p vets_to_vals(res)
|
||
end
|