feat(csharp) .NET 8.0 code migration

.github/workflows/dotnet.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        dotnet-version: ["6.0.x"]
+        dotnet-version: ["8.0.x"]
 
     steps:
     - uses: actions/checkout@v4

codes/Dockerfile

@@ -22,7 +22,7 @@ RUN for LANG in $LANGS; do \
                 wget https://packages.microsoft.com/config/ubuntu/20.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb && \
                 dpkg -i packages-microsoft-prod.deb && \
                 apt-get update && \
-                apt-get install -y dotnet-sdk-6.0 ;; \
+                apt-get install -y dotnet-sdk-8.0 ;; \
             # More languages...
             *) \
                 echo "Warning: No installation workflow for $LANG" ;; \

codes/csharp/.editorconfig

@@ -4,3 +4,76 @@ csharp_new_line_before_open_brace = none
 csharp_new_line_before_else = false
 csharp_new_line_before_catch = false
 csharp_new_line_before_finally = false
+csharp_indent_labels = one_less_than_current
+csharp_using_directive_placement = outside_namespace:silent
+csharp_prefer_simple_using_statement = true:suggestion
+csharp_prefer_braces = true:silent
+csharp_style_namespace_declarations = block_scoped:silent
+csharp_style_prefer_method_group_conversion = true:silent
+csharp_style_prefer_top_level_statements = true:silent
+csharp_style_prefer_primary_constructors = true:suggestion
+csharp_style_expression_bodied_methods = false:silent
+csharp_style_expression_bodied_constructors = false:silent
+csharp_style_expression_bodied_operators = false:silent
+csharp_style_expression_bodied_properties = true:silent
+csharp_style_expression_bodied_indexers = true:silent
+csharp_style_expression_bodied_accessors = true:silent
+csharp_style_expression_bodied_lambdas = true:silent
+
+# CS8981: The type name only contains lower-cased ascii characters. Such names may become reserved for the language.
+dotnet_diagnostic.CS8981.severity = silent
+
+# IDE1006: Naming Styles
+dotnet_diagnostic.IDE1006.severity = silent
+
+[*.{cs,vb}]
+#### Naming styles ####
+
+# Naming rules
+
+dotnet_naming_rule.interface_should_be_begins_with_i.severity = suggestion
+dotnet_naming_rule.interface_should_be_begins_with_i.symbols = interface
+dotnet_naming_rule.interface_should_be_begins_with_i.style = begins_with_i
+
+dotnet_naming_rule.types_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.types_should_be_pascal_case.symbols = types
+dotnet_naming_rule.types_should_be_pascal_case.style = pascal_case
+
+dotnet_naming_rule.non_field_members_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.non_field_members_should_be_pascal_case.symbols = non_field_members
+dotnet_naming_rule.non_field_members_should_be_pascal_case.style = pascal_case
+
+# Symbol specifications
+
+dotnet_naming_symbols.interface.applicable_kinds = interface
+dotnet_naming_symbols.interface.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.interface.required_modifiers = 
+
+dotnet_naming_symbols.types.applicable_kinds = class, struct, interface, enum
+dotnet_naming_symbols.types.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.types.required_modifiers = 
+
+dotnet_naming_symbols.non_field_members.applicable_kinds = property, event, method
+dotnet_naming_symbols.non_field_members.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.non_field_members.required_modifiers = 
+
+# Naming styles
+
+dotnet_naming_style.begins_with_i.required_prefix = I
+dotnet_naming_style.begins_with_i.required_suffix = 
+dotnet_naming_style.begins_with_i.word_separator = 
+dotnet_naming_style.begins_with_i.capitalization = pascal_case
+
+dotnet_naming_style.pascal_case.required_prefix = 
+dotnet_naming_style.pascal_case.required_suffix = 
+dotnet_naming_style.pascal_case.word_separator = 
+dotnet_naming_style.pascal_case.capitalization = pascal_case
+
+dotnet_naming_style.pascal_case.required_prefix = 
+dotnet_naming_style.pascal_case.required_suffix = 
+dotnet_naming_style.pascal_case.word_separator = 
+dotnet_naming_style.pascal_case.capitalization = pascal_case
+dotnet_style_operator_placement_when_wrapping = beginning_of_line
+tab_width = 4
+indent_size = 4
+end_of_line = crlf

codes/csharp/chapter_array_and_linkedlist/array.cs

@@ -78,7 +78,7 @@ public static void Test() {
         // 初始化数组
         int[] arr = new int[5];
         Console.WriteLine("数组 arr = " + ToString(arr));
-        int[] nums = { 1, 3, 2, 5, 4 };
+        int[] nums = [1, 3, 2, 5, 4];
         Console.WriteLine("数组 nums = " + ToString(nums));
 
         // 随机访问

codes/csharp/chapter_array_and_linkedlist/linked_list.cs

@@ -23,7 +23,7 @@ public static void Remove(ListNode n0) {
     }
 
     /* 访问链表中索引为 index 的节点 */
-    public static ListNode? Access(ListNode head, int index) {
+    public static ListNode? Access(ListNode? head, int index) {
         for (int i = 0; i < index; i++) {
             if (head == null)
                 return null;
@@ -33,7 +33,7 @@ public static void Remove(ListNode n0) {
     }
 
     /* 在链表中查找值为 target 的首个节点 */
-    public static int Find(ListNode head, int target) {
+    public static int Find(ListNode? head, int target) {
         int index = 0;
         while (head != null) {
             if (head.val == target)

codes/csharp/chapter_array_and_linkedlist/list.cs

@@ -11,8 +11,8 @@ public class list {
     public void Test() {
 
         /* 初始化列表 */
-        int[] numbers = new int[] { 1, 3, 2, 5, 4 };
-        List<int> nums = numbers.ToList();
+        int[] numbers = [1, 3, 2, 5, 4];
+        List<int> nums = [.. numbers];
         Console.WriteLine("列表 nums = " + string.Join(",", nums));
 
         /* 访问元素 */
@@ -55,7 +55,7 @@ public void Test() {
         }
 
         /* 拼接两个列表 */
-        List<int> nums1 = new() { 6, 8, 7, 10, 9 };
+        List<int> nums1 = [6, 8, 7, 10, 9];
         nums.AddRange(nums1);
         Console.WriteLine("将列表 nums1 拼接到 nums 之后，得到 nums = " + string.Join(",", nums));
 

codes/csharp/chapter_backtracking/n_queens.cs

@@ -12,7 +12,7 @@ static void Backtrack(int row, int n, List<List<string>> state, List<List<List<s
             bool[] cols, bool[] diags1, bool[] diags2) {
         // 当放置完所有行时，记录解
         if (row == n) {
-            List<List<string>> copyState = new();
+            List<List<string>> copyState = [];
             foreach (List<string> sRow in state) {
                 copyState.Add(new List<string>(sRow));
             }
@@ -41,9 +41,9 @@ static void Backtrack(int row, int n, List<List<string>> state, List<List<List<s
     /* 求解 N 皇后 */
     static List<List<List<string>>> NQueens(int n) {
         // 初始化 n*n 大小的棋盘，其中 'Q' 代表皇后，'#' 代表空位
-        List<List<string>> state = new();
+        List<List<string>> state = [];
         for (int i = 0; i < n; i++) {
-            List<string> row = new();
+            List<string> row = [];
             for (int j = 0; j < n; j++) {
                 row.Add("#");
             }
@@ -52,7 +52,7 @@ static List<List<List<string>>> NQueens(int n) {
         bool[] cols = new bool[n]; // 记录列是否有皇后
         bool[] diags1 = new bool[2 * n - 1]; // 记录主对角线是否有皇后
         bool[] diags2 = new bool[2 * n - 1]; // 记录副对角线是否有皇后
-        List<List<List<string>>> res = new();
+        List<List<List<string>>> res = [];
 
         Backtrack(0, n, state, res, cols, diags1, diags2);
 

codes/csharp/chapter_backtracking/permutations_i.cs

@@ -33,14 +33,14 @@ static void Backtrack(List<int> state, int[] choices, bool[] selected, List<List
 
     /* 全排列 I */
     static List<List<int>> PermutationsI(int[] nums) {
-        List<List<int>> res = new();
-        Backtrack(new List<int>(), nums, new bool[nums.Length], res);
+        List<List<int>> res = [];
+        Backtrack([], nums, new bool[nums.Length], res);
         return res;
     }
 
     [Test]
     public void Test() {
-        int[] nums = { 1, 2, 3 };
+        int[] nums = [1, 2, 3];
 
         List<List<int>> res = PermutationsI(nums);
 

codes/csharp/chapter_backtracking/permutations_ii.cs

@@ -15,7 +15,7 @@ static void Backtrack(List<int> state, int[] choices, bool[] selected, List<List
             return;
         }
         // 遍历所有选择
-        ISet<int> duplicated = new HashSet<int>();
+        HashSet<int> duplicated = [];
         for (int i = 0; i < choices.Length; i++) {
             int choice = choices[i];
             // 剪枝：不允许重复选择元素 且 不允许重复选择相等元素
@@ -35,14 +35,14 @@ static void Backtrack(List<int> state, int[] choices, bool[] selected, List<List
 
     /* 全排列 II */
     static List<List<int>> PermutationsII(int[] nums) {
-        List<List<int>> res = new();
-        Backtrack(new List<int>(), nums, new bool[nums.Length], res);
+        List<List<int>> res = [];
+        Backtrack([], nums, new bool[nums.Length], res);
         return res;
     }
 
     [Test]
     public void Test() {
-        int[] nums = { 1, 2, 2 };
+        int[] nums = [1, 2, 2];
 
         List<List<int>> res = PermutationsII(nums);
 

codes/csharp/chapter_backtracking/preorder_traversal_i_compact.cs

@@ -7,10 +7,10 @@
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_i_compact {
-    static List<TreeNode> res;
+    static readonly List<TreeNode> res = [];
 
     /* 前序遍历：例题一 */
-    static void PreOrder(TreeNode root) {
+    static void PreOrder(TreeNode? root) {
         if (root == null) {
             return;
         }
@@ -24,12 +24,11 @@ static void PreOrder(TreeNode root) {
 
     [Test]
     public void Test() {
-        TreeNode root = TreeNode.ListToTree(new List<int?> { 1, 7, 3, 4, 5, 6, 7 });
+        TreeNode? root = TreeNode.ListToTree([1, 7, 3, 4, 5, 6, 7]);
         Console.WriteLine("\n初始化二叉树");
         PrintUtil.PrintTree(root);
 
         // 前序遍历
-        res = new List<TreeNode>();
         PreOrder(root);
 
         Console.WriteLine("\n输出所有值为 7 的节点");

codes/csharp/chapter_backtracking/preorder_traversal_ii_compact.cs

@@ -7,11 +7,11 @@
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_ii_compact {
-    static List<TreeNode> path;
-    static List<List<TreeNode>> res;
+    static readonly List<TreeNode> path = [];
+    static readonly List<List<TreeNode>> res = [];
 
     /* 前序遍历：例题二 */
-    static void PreOrder(TreeNode root) {
+    static void PreOrder(TreeNode? root) {
         if (root == null) {
             return;
         }
@@ -29,13 +29,11 @@ static void PreOrder(TreeNode root) {
 
     [Test]
     public void Test() {
-        TreeNode root = TreeNode.ListToTree(new List<int?> { 1, 7, 3, 4, 5, 6, 7 });
+        TreeNode? root = TreeNode.ListToTree([1, 7, 3, 4, 5, 6, 7]);
         Console.WriteLine("\n初始化二叉树");
         PrintUtil.PrintTree(root);
 
         // 前序遍历
-        path = new List<TreeNode>();
-        res = new List<List<TreeNode>>();
         PreOrder(root);
 
         Console.WriteLine("\n输出所有根节点到节点 7 的路径");

codes/csharp/chapter_backtracking/preorder_traversal_iii_compact.cs

@@ -7,11 +7,11 @@
 namespace hello_algo.chapter_backtracking;
 
 public class preorder_traversal_iii_compact {
-    static List<TreeNode> path;
-    static List<List<TreeNode>> res;
+    static readonly List<TreeNode> path = [];
+    static readonly List<List<TreeNode>> res = [];
 
     /* 前序遍历：例题三 */
-    static void PreOrder(TreeNode root) {
+    static void PreOrder(TreeNode? root) {
         // 剪枝
         if (root == null || root.val == 3) {
             return;
@@ -30,13 +30,11 @@ static void PreOrder(TreeNode root) {
 
     [Test]
     public void Test() {
-        TreeNode root = TreeNode.ListToTree(new List<int?> { 1, 7, 3, 4, 5, 6, 7 });
+        TreeNode? root = TreeNode.ListToTree([1, 7, 3, 4, 5, 6, 7]);
         Console.WriteLine("\n初始化二叉树");
         PrintUtil.PrintTree(root);
 
         // 前序遍历
-        path = new List<TreeNode>();
-        res = new List<List<TreeNode>>();
         PreOrder(root);
 
         Console.WriteLine("\n输出所有根节点到节点 7 的路径，路径中不包含值为 3 的节点");

codes/csharp/chapter_backtracking/preorder_traversal_iii_template.cs

@@ -46,7 +46,7 @@ static void Backtrack(List<TreeNode> state, List<TreeNode> choices, List<List<Tr
                 // 尝试：做出选择，更新状态
                 MakeChoice(state, choice);
                 // 进行下一轮选择
-                Backtrack(state, new List<TreeNode> { choice.left, choice.right }, res);
+                Backtrack(state, [choice.left!, choice.right!], res);
                 // 回退：撤销选择，恢复到之前的状态
                 UndoChoice(state, choice);
             }
@@ -55,14 +55,14 @@ static void Backtrack(List<TreeNode> state, List<TreeNode> choices, List<List<Tr
 
     [Test]
     public void Test() {
-        TreeNode root = TreeNode.ListToTree(new List<int?> { 1, 7, 3, 4, 5, 6, 7 });
+        TreeNode? root = TreeNode.ListToTree([1, 7, 3, 4, 5, 6, 7]);
         Console.WriteLine("\n初始化二叉树");
         PrintUtil.PrintTree(root);
 
         // 回溯算法
-        List<List<TreeNode>> res = new();
-        List<TreeNode> choices = new() { root };
-        Backtrack(new List<TreeNode>(), choices, res);
+        List<List<TreeNode>> res = [];
+        List<TreeNode> choices = [root!];
+        Backtrack([], choices, res);
 
         Console.WriteLine("\n输出所有根节点到节点 7 的路径，要求路径中不包含值为 3 的节点");
         foreach (List<TreeNode> path in res) {

codes/csharp/chapter_backtracking/subset_sum_i.cs

@@ -33,17 +33,17 @@ public static void Backtrack(List<int> state, int target, int[] choices, int sta
 
     /* 求解子集和 I */
     public static List<List<int>> SubsetSumI(int[] nums, int target) {
-        List<int> state = new(); // 状态（子集）
+        List<int> state = []; // 状态（子集）
         Array.Sort(nums); // 对 nums 进行排序
         int start = 0; // 遍历起始点
-        List<List<int>> res = new(); // 结果列表（子集列表）
+        List<List<int>> res = []; // 结果列表（子集列表）
         Backtrack(state, target, nums, start, res);
         return res;
     }
 
     [Test]
     public void Test() {
-        int[] nums = { 3, 4, 5 };
+        int[] nums = [3, 4, 5];
         int target = 9;
         List<List<int>> res = SubsetSumI(nums, target);
         Console.WriteLine("输入数组 nums = " + string.Join(", ", nums) + ", target = " + target);

codes/csharp/chapter_backtracking/subset_sum_i_naive.cs

@@ -31,16 +31,16 @@ public static void Backtrack(List<int> state, int target, int total, int[] choic
 
     /* 求解子集和 I（包含重复子集） */
     public static List<List<int>> SubsetSumINaive(int[] nums, int target) {
-        List<int> state = new(); // 状态（子集）
+        List<int> state = []; // 状态（子集）
         int total = 0; // 子集和
-        List<List<int>> res = new(); // 结果列表（子集列表）
+        List<List<int>> res = []; // 结果列表（子集列表）
         Backtrack(state, target, total, nums, res);
         return res;
     }
 
     [Test]
     public void Test() {
-        int[] nums = { 3, 4, 5 };
+        int[] nums = [3, 4, 5];
         int target = 9;
         List<List<int>> res = SubsetSumINaive(nums, target);
         Console.WriteLine("输入数组 nums = " + string.Join(", ", nums) + ", target = " + target);

codes/csharp/chapter_backtracking/subset_sum_ii.cs

@@ -38,17 +38,17 @@ public static void Backtrack(List<int> state, int target, int[] choices, int sta
 
     /* 求解子集和 II */
     public static List<List<int>> SubsetSumII(int[] nums, int target) {
-        List<int> state = new(); // 状态（子集）
+        List<int> state = []; // 状态（子集）
         Array.Sort(nums); // 对 nums 进行排序
         int start = 0; // 遍历起始点
-        List<List<int>> res = new(); // 结果列表（子集列表）
+        List<List<int>> res = []; // 结果列表（子集列表）
         Backtrack(state, target, nums, start, res);
         return res;
     }
 
     [Test]
     public void Test() {
-        int[] nums = { 4, 4, 5 };
+        int[] nums = [4, 4, 5];
         int target = 9;
         List<List<int>> res = SubsetSumII(nums, target);
         Console.WriteLine("输入数组 nums = " + string.Join(", ", nums) + ", target = " + target);