mirror of
https://github.com/krahets/hello-algo.git
synced 2025-10-31 18:37:48 +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
59 lines
2.0 KiB
C#
59 lines
2.0 KiB
C#
/**
|
||
* File: graph_bfs.cs
|
||
* Created Time: 2023-03-08
|
||
* Author: hpstory (hpstory1024@163.com)
|
||
*/
|
||
|
||
namespace hello_algo.chapter_graph;
|
||
|
||
public class graph_bfs {
|
||
/* 廣度優先走訪 */
|
||
// 使用鄰接表來表示圖，以便獲取指定頂點的所有鄰接頂點
|
||
List<Vertex> GraphBFS(GraphAdjList graph, Vertex startVet) {
|
||
// 頂點走訪序列
|
||
List<Vertex> res = [];
|
||
// 雜湊集合，用於記錄已被訪問過的頂點
|
||
HashSet<Vertex> visited = [startVet];
|
||
// 佇列用於實現 BFS
|
||
Queue<Vertex> que = new();
|
||
que.Enqueue(startVet);
|
||
// 以頂點 vet 為起點，迴圈直至訪問完所有頂點
|
||
while (que.Count > 0) {
|
||
Vertex vet = que.Dequeue(); // 佇列首頂點出隊
|
||
res.Add(vet); // 記錄訪問頂點
|
||
foreach (Vertex adjVet in graph.adjList[vet]) {
|
||
if (visited.Contains(adjVet)) {
|
||
continue; // 跳過已被訪問的頂點
|
||
}
|
||
que.Enqueue(adjVet); // 只入列未訪問的頂點
|
||
visited.Add(adjVet); // 標記該頂點已被訪問
|
||
}
|
||
}
|
||
|
||
// 返回頂點走訪序列
|
||
return res;
|
||
}
|
||
|
||
[Test]
|
||
public void Test() {
|
||
/* 初始化無向圖 */
|
||
Vertex[] v = Vertex.ValsToVets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
|
||
Vertex[][] 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]]
|
||
];
|
||
|
||
GraphAdjList graph = new(edges);
|
||
Console.WriteLine("\n初始化後，圖為");
|
||
graph.Print();
|
||
|
||
/* 廣度優先走訪 */
|
||
List<Vertex> res = GraphBFS(graph, v[0]);
|
||
Console.WriteLine("\n廣度優先走訪（BFS）頂點序列為");
|
||
Console.WriteLine(string.Join(" ", Vertex.VetsToVals(res)));
|
||
}
|
||
}
|