feat(csharp) .NET 8.0 code migration (#966)

* .net 8.0 migration

* update docs

* revert change

* revert change and update appendix docs

* remove static

* Update binary_search_insertion.cs

* Update binary_search_insertion.cs

* Update binary_search_edge.cs

* Update binary_search_insertion.cs

* Update binary_search_edge.cs

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/csharp/chapter_graph/graph_adjacency_list.cs

@@ -13,7 +13,7 @@ public class GraphAdjList {
 
     /* 构造函数 */
     public GraphAdjList(Vertex[][] edges) {
-        this.adjList = new Dictionary<Vertex, List<Vertex>>();
+        adjList = [];
         // 添加所有顶点和边
         foreach (Vertex[] edge in edges) {
             AddVertex(edge[0]);
@@ -23,7 +23,7 @@ public class GraphAdjList {
     }
 
     /* 获取顶点数量 */
-    public int Size() {
+    int Size() {
         return adjList.Count;
     }
 
@@ -50,7 +50,7 @@ public class GraphAdjList {
         if (adjList.ContainsKey(vet))
             return;
         // 在邻接表中添加一个新链表
-        adjList.Add(vet, new List<Vertex>());
+        adjList.Add(vet, []);
     }
 
     /* 删除顶点 */
@@ -69,7 +69,7 @@ public class GraphAdjList {
     public void Print() {
         Console.WriteLine("邻接表 =");
         foreach (KeyValuePair<Vertex, List<Vertex>> pair in adjList) {
-            List<int> tmp = new();
+            List<int> tmp = [];
             foreach (Vertex vertex in pair.Value)
                 tmp.Add(vertex.val);
             Console.WriteLine(pair.Key.val + ": [" + string.Join(", ", tmp) + "],");
@@ -81,10 +81,16 @@ public class graph_adjacency_list {
     [Test]
     public void Test() {
         /* 初始化无向图 */
-        Vertex[] v = Vertex.ValsToVets(new int[] { 1, 3, 2, 5, 4 });
-        Vertex[][] edges = new Vertex[][] { new Vertex[] { v[0], v[1] }, new Vertex[] { v[0], v[3] },
-                                            new Vertex[] { v[1], v[2] }, new Vertex[] { v[2], v[3] },
-                                            new Vertex[] { v[2], v[4] }, new Vertex[] { v[3], v[4] } };
+        Vertex[] v = Vertex.ValsToVets([1, 3, 2, 5, 4]);
+        Vertex[][] edges =
+        [
+            [v[0], v[1]],
+            [v[0], v[3]],
+            [v[1], v[2]],
+            [v[2], v[3]],
+            [v[2], v[4]],
+            [v[3], v[4]] 
+        ];
         GraphAdjList graph = new(edges);
         Console.WriteLine("\n初始化后，图为");
         graph.Print();

codes/csharp/chapter_graph/graph_adjacency_matrix.cs

@@ -8,13 +8,13 @@ namespace hello_algo.chapter_graph;
 
 /* 基于邻接矩阵实现的无向图类 */
 class GraphAdjMat {
-    readonly List<int> vertices;     // 顶点列表，元素代表“顶点值”，索引代表“顶点索引”
-    readonly List<List<int>> adjMat; // 邻接矩阵，行列索引对应“顶点索引”
+    List<int> vertices;     // 顶点列表，元素代表“顶点值”，索引代表“顶点索引”
+    List<List<int>> adjMat; // 邻接矩阵，行列索引对应“顶点索引”
 
     /* 构造函数 */
     public GraphAdjMat(int[] vertices, int[][] edges) {
-        this.vertices = new List<int>();
-        this.adjMat = new List<List<int>>();
+        this.vertices = [];
+        this.adjMat = [];
         // 添加顶点
         foreach (int val in vertices) {
             AddVertex(val);
@@ -27,7 +27,7 @@ class GraphAdjMat {
     }
 
     /* 获取顶点数量 */
-    public int Size() {
+    int Size() {
         return vertices.Count;
     }
 
@@ -97,10 +97,16 @@ public class graph_adjacency_matrix {
     public void Test() {
         /* 初始化无向图 */
         // 请注意，edges 元素代表顶点索引，即对应 vertices 元素索引
-        int[] vertices = { 1, 3, 2, 5, 4 };
-        int[][] edges = new int[][] { new int[] { 0, 1 }, new int[] { 0, 3 },
-                                      new int[] { 1, 2 }, new int[] { 2, 3 },
-                                      new int[] { 2, 4 }, new int[] { 3, 4 } };
+        int[] vertices = [1, 3, 2, 5, 4];
+        int[][] edges = 
+        [
+            [0, 1],
+            [0, 3],
+            [1, 2],
+            [2, 3],
+            [2, 4],
+            [3, 4]
+        ];
         GraphAdjMat graph = new(vertices, edges);
         Console.WriteLine("\n初始化后，图为");
         graph.Print();

codes/csharp/chapter_graph/graph_bfs.cs

@@ -9,11 +9,11 @@ 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) {
+    List<Vertex> GraphBFS(GraphAdjList graph, Vertex startVet) {
         // 顶点遍历序列
-        List<Vertex> res = new();
+        List<Vertex> res = [];
         // 哈希表，用于记录已被访问过的顶点
-        HashSet<Vertex> visited = new() { startVet };
+        HashSet<Vertex> visited = [startVet];
         // 队列用于实现 BFS
         Queue<Vertex> que = new();
         que.Enqueue(startVet);
@@ -37,14 +37,14 @@ public class graph_bfs {
     [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] }
-        };
+        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");

codes/csharp/chapter_graph/graph_dfs.cs

@@ -8,7 +8,7 @@ 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) {
+    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
@@ -23,11 +23,11 @@ public class graph_dfs {
 
     /* 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) {
+    List<Vertex> GraphDFS(GraphAdjList graph, Vertex startVet) {
         // 顶点遍历序列
-        List<Vertex> res = new();
+        List<Vertex> res = [];
         // 哈希表，用于记录已被访问过的顶点
-        HashSet<Vertex> visited = new();
+        HashSet<Vertex> visited = [];
         DFS(graph, visited, res, startVet);
         return res;
     }
@@ -35,12 +35,12 @@ public class graph_dfs {
     [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] },
-        };
+        Vertex[] v = Vertex.ValsToVets([0, 1, 2, 3, 4, 5, 6]);
+        Vertex[][] edges =
+        [
+            [v[0], v[1]], [v[0], v[3]], [v[1], v[2]],
+            [v[2], v[5]], [v[4], v[5]], [v[5], v[6]],
+        ];
 
         GraphAdjList graph = new(edges);
         Console.WriteLine("\n初始化后，图为");