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feature: Add csharp code graph_bfs and graph_dfs (#404)

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* add csharp code graph_bfs and graph_dfs, modify graph adjacency list class inaccessable

* remove unnecessary using

* fix code style issue in comments
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hpstory 2023-03-08 19:16:46 +08:00 committed by GitHub
parent 590b532606
commit b6c9b01d96
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3 changed files with 134 additions and 2 deletions
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4
codes/csharp/chapter_graph/graph_adjacency_list.cs
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@ -10,10 +10,10 @@ using NUnit.Framework;
namespace hello_algo.chapter_graph;
/* 基于邻接表实现的无向图类 */
class GraphAdjList
public class GraphAdjList
{
// 邻接表，key: 顶点，value：该顶点的所有邻接顶点
Dictionary<Vertex, List<Vertex>> adjList;
public Dictionary<Vertex, List<Vertex>> adjList;
/* 构造函数 */
public GraphAdjList(Vertex[][] edges)

68
codes/csharp/chapter_graph/graph_bfs.cs Normal file
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@ -0,0 +1,68 @@
/**
* File: graph_bfs.cs
* Created Time: 2023-03-08
* Author: hpstory (hpstory1024@163.com)
*/
using hello_algo.include;
using NUnit.Framework;
namespace hello_algo.chapter_graph
{
public class graph_bfs
{
/* 广度优先遍历 BFS */
// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
public static List<Vertex> graphBFS(GraphAdjList graph, Vertex startVet)
{
// 顶点遍历序列
List<Vertex> res = new List<Vertex>();
// 哈希表，用于记录已被访问过的顶点
HashSet<Vertex> visited = new HashSet<Vertex>() { startVet };
// 队列用于实现 BFS
Queue<Vertex> que = new Queue<Vertex>();
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; // 跳过已被访问过的顶点
}
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(new int[10] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
Vertex[][] edges = new Vertex[12][]
{
new Vertex[2] { v[0], v[1] }, new Vertex[2] { v[0], v[3] }, new Vertex[2] { v[1], v[2] },
new Vertex[2] { v[1], v[4] }, new Vertex[2] { v[2], v[5] }, new Vertex[2] { v[3], v[4] },
new Vertex[2] { v[3], v[6] }, new Vertex[2] { v[4], v[5] }, new Vertex[2] { v[4], v[7] },
new Vertex[2] { v[5], v[8] }, new Vertex[2] { v[6], v[7] }, new Vertex[2] { v[7], v[8] }
};
GraphAdjList graph = new GraphAdjList(edges);
Console.WriteLine("\n初始化后，图为");
graph.print();
/* 广度优先遍历 BFS */
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)));
}
}
}

64
codes/csharp/chapter_graph/graph_dfs.cs Normal file
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@ -0,0 +1,64 @@
/**
* File: graph_dfs.cs
* Created Time: 2023-03-08
* Author: hpstory (hpstory1024@163.com)
*/
using hello_algo.include;
using NUnit.Framework;
namespace hello_algo.chapter_graph
{
public class graph_dfs
{
/* 深度优先遍历 DFS 辅助函数 */
public void dfs(GraphAdjList graph, HashSet<Vertex> visited, List<Vertex> res, Vertex vet)
{
res.Add(vet); // 记录访问顶点
visited.Add(vet); // 标记该顶点已被访问
// 遍历该顶点的所有邻接顶点
foreach (Vertex adjVet in graph.adjList[vet])
{
if (visited.Contains(adjVet))
{
continue; // 跳过已被访问过的顶点
}
// 递归访问邻接顶点
dfs(graph, visited, res, adjVet);
}
}
/* 深度优先遍历 DFS */
// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
public List<Vertex> graphDFS(GraphAdjList graph, Vertex startVet)
{
// 顶点遍历序列
List<Vertex> res = new List<Vertex>();
// 哈希表，用于记录已被访问过的顶点
HashSet<Vertex> visited = new HashSet<Vertex>();
dfs(graph, visited, res, startVet);
return res;
}
[Test]
public void Test()
{
/* 初始化无向图 */
Vertex[] v = Vertex.valsToVets(new int[7] { 0, 1, 2, 3, 4, 5, 6 });
Vertex[][] edges = new Vertex[6][]
{
new Vertex[2] { v[0], v[1] }, new Vertex[2] { v[0], v[3] }, new Vertex[2] { v[1], v[2] },
new Vertex[2] { v[2], v[5] }, new Vertex[2] { v[4], v[5] }, new Vertex[2] { v[5], v[6] },
};
GraphAdjList graph = new GraphAdjList(edges);
Console.WriteLine("\n初始化后，图为");
graph.print();
/* 深度优先遍历 DFS */
List<Vertex> res = graphDFS(graph, v[0]);
Console.WriteLine("\n深度优先遍历（DFS）顶点序列为");
Console.WriteLine(string.Join(" ", Vertex.vetsToVals(res)));
}
}
}