You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
hello-algo/codes/csharp/chapter_graph/graph_bfs.cs

59 lines
2.0 KiB

/**
* File: graph_bfs.cs
* Created Time: 2023-03-08
* Author: hpstory (hpstory1024@163.com)
*/
namespace hello_algo.chapter_graph;
public class graph_bfs {
/* 广度优先遍历 */
// 使用邻接表来表示图,以便获取指定顶点的所有邻接顶点
List<Vertex> GraphBFS(GraphAdjList graph, Vertex startVet) {
// 顶点遍历序列
List<Vertex> res = [];
// 哈希表,用于记录已被访问过的顶点
HashSet<Vertex> visited = [startVet];
// 队列用于实现 BFS
Queue<Vertex> que = new();
que.Enqueue(startVet);
// 以顶点 vet 为起点,循环直至访问完所有顶点
while (que.Count > 0) {
Vertex vet = que.Dequeue(); // 队首顶点出队
res.Add(vet); // 记录访问顶点
foreach (Vertex adjVet in graph.adjList[vet]) {
if (visited.Contains(adjVet)) {
continue; // 跳过已被访问的顶点
}
que.Enqueue(adjVet); // 只入队未访问的顶点
visited.Add(adjVet); // 标记该顶点已被访问
}
}
// 返回顶点遍历序列
return res;
}
[Test]
public void Test() {
/* 初始化无向图 */
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初始化后图为");
graph.Print();
/* 广度优先遍历 */
List<Vertex> res = GraphBFS(graph, v[0]);
Console.WriteLine("\n广度优先遍历BFS顶点序列为");
Console.WriteLine(string.Join(" ", Vertex.VetsToVals(res)));
}
}