fix(csharp): reformat csharp codes and docs (#652)

* fix(csharp): reformat the C# codes and docs

* Update time_complexity.md

---------

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

codes/csharp/chapter_array_and_linkedlist/list.cs

@@ -45,7 +45,7 @@ public class list {
 
         /* 通过索引遍历列表 */
         int count = 0;
-        for (int i = 0; i < list.Count(); i++) {
+        for (int i = 0; i < list.Count; i++) {
             count++;
         }
 

codes/csharp/chapter_array_and_linkedlist/my_list.cs

@@ -87,7 +87,7 @@ class MyList {
     /* 列表扩容 */
     public void extendCapacity() {
         // 新建一个长度为 numsCapacity * extendRatio 的数组，并将原数组拷贝到新数组
-        System.Array.Resize(ref nums, numsCapacity * extendRatio);
+        Array.Resize(ref nums, numsCapacity * extendRatio);
         // 更新列表容量
         numsCapacity = nums.Length;
     }

codes/csharp/chapter_computational_complexity/time_complexity.cs

@@ -87,9 +87,7 @@ public class time_complexity {
             for (int j = 0; j < i; j++) {
                 if (nums[j] > nums[j + 1]) {
                     // 交换 nums[j] 与 nums[j + 1]
-                    int tmp = nums[j];
+                    (nums[j + 1], nums[j]) = (nums[j], nums[j + 1]);
-                    nums[j] = nums[j + 1];
-                    nums[j + 1] = tmp;
                     count += 3;  // 元素交换包含 3 个单元操作
                 }
             }

codes/csharp/chapter_searching/two_sum.cs

@@ -17,7 +17,7 @@ public class two_sum {
                     return new int[] { i, j };
             }
         }
-        return new int[0];
+        return Array.Empty<int>();
     }
 
     /* 方法二：辅助哈希表 */
@@ -32,7 +32,7 @@ public class two_sum {
             }
             dic.Add(nums[i], i);
         }
-        return new int[0];
+        return Array.Empty<int>();
     }
 
     [Test]

codes/csharp/chapter_stack_and_queue/queue.cs

@@ -29,11 +29,11 @@ public class queue {
         Console.WriteLine("出队元素 pop = " + pop + "，出队后 queue = " + string.Join(",", queue));
 
         /* 获取队列的长度 */
-        int size = queue.Count();
+        int size = queue.Count;
         Console.WriteLine("队列长度 size = " + size);
 
         /* 判断队列是否为空 */
-        bool isEmpty = queue.Count() == 0;
+        bool isEmpty = queue.Count == 0;
         Console.WriteLine("队列是否为空 = " + isEmpty);
     }
 }

codes/csharp/chapter_stack_and_queue/stack.cs

@@ -30,11 +30,11 @@ public class stack {
         Console.WriteLine("出栈元素 pop = " + pop + "，出栈后 stack = " + string.Join(",", stack));
 
         /* 获取栈的长度 */
-        int size = stack.Count();
+        int size = stack.Count;
         Console.WriteLine("栈的长度 size = " + size);
 
         /* 判断是否为空 */
-        bool isEmpty = stack.Count() == 0;
+        bool isEmpty = stack.Count == 0;
         Console.WriteLine("栈是否为空 = " + isEmpty);
     }
 }

docs/chapter_array_and_linkedlist/linked_list.md

@@ -111,8 +111,7 @@
 
     ```csharp title=""
     /* 链表节点类 */
-    class ListNode
+    class ListNode {
-    {
         int val;         // 节点值
         ListNode next;   // 指向下一节点的引用
         ListNode(int x) => val = x;  //构造函数

docs/chapter_array_and_linkedlist/list.md

@@ -539,15 +539,13 @@
     ```csharp title="list.cs"
     /* 通过索引遍历列表 */
     int count = 0;
-    for (int i = 0; i < list.Count(); i++)
+    for (int i = 0; i < list.Count; i++) {
-    {
         count++;
     }
 
     /* 直接遍历列表元素 */
     count = 0;
-    foreach (int n in list)
+    foreach (int n in list) {
-    {
         count++;
     }
     ```

docs/chapter_computational_complexity/space_complexity.md

@@ -200,22 +200,19 @@
 
     ```csharp title=""
     /* 类 */
-    class Node
+    class Node {
-    {
         int val;
         Node next;
         Node(int x) { val = x; }
     }
 
     /* 函数 */
-    int function()
+    int function() {
-    {
         // do something...
         return 0;
     }
 
-    int algorithm(int n)          // 输入数据
+    int algorithm(int n) {        // 输入数据
-    {
         const int a = 0;          // 暂存数据（常量）
         int b = 0;                // 暂存数据（变量）
         Node node = new Node(0);  // 暂存数据（对象）
@@ -376,12 +373,10 @@
 === "C#"
 
     ```csharp title=""
-    void algorithm(int n)
+    void algorithm(int n) {
-    {
         int a = 0;                   // O(1)
         int[] b = new int[10000];    // O(1)
-        if (n > 10)
+        if (n > 10) {
-        {
             int[] nums = new int[n]; // O(n)
         }
     }
@@ -564,22 +559,18 @@
 === "C#"
 
     ```csharp title=""
-    int function()
+    int function() {
-    {
         // do something
         return 0;
     }
     /* 循环 O(1) */
-    void loop(int n)
+    void loop(int n) {
-    {
+        for (int i = 0; i < n; i++) {
-        for (int i = 0; i < n; i++)
-        {
             function();
         }
     }
     /* 递归 O(n) */
-    int recur(int n)
+    int recur(int n) {
-    {
         if (n == 1) return 1;
         return recur(n - 1);
     }

docs/chapter_computational_complexity/time_complexity.md

@@ -121,14 +121,12 @@ $$
 
     ```csharp title=""
     // 在某运行平台下
-    void algorithm(int n)
+    void algorithm(int n) {
-    {
         int a = 2;  // 1 ns
         a = a + 1;  // 1 ns
         a = a * 2;  // 10 ns
         // 循环 n 次
-        for (int i = 0; i < n; i++)
+        for (int i = 0; i < n; i++) {  // 1 ns ，每轮都要执行 i++
-        {  // 1 ns ，每轮都要执行 i++
             Console.WriteLine(0);      // 5 ns
         }
     }
@@ -329,23 +327,18 @@ $$
 
     ```csharp title=""
     // 算法 A 时间复杂度：常数阶
-    void algorithm_A(int n)
+    void algorithm_A(int n) {
-    {
         Console.WriteLine(0);
     }
     // 算法 B 时间复杂度：线性阶
-    void algorithm_B(int n)
+    void algorithm_B(int n) {
-    {
+        for (int i = 0; i < n; i++) {
-        for (int i = 0; i < n; i++)
-        {
             Console.WriteLine(0);
         }
     }
     // 算法 C 时间复杂度：常数阶
-    void algorithm_C(int n)
+    void algorithm_C(int n) {
-    {
+        for (int i = 0; i < 1000000; i++) {
-        for (int i = 0; i < 1000000; i++)
-        {
             Console.WriteLine(0);
         }
     }
@@ -518,14 +511,12 @@ $$
 === "C#"
 
     ```csharp title=""
-    void algorithm(int n)
+    void algorithm(int n) {
-    {
         int a = 1;  // +1
         a = a + 1;  // +1
         a = a * 2;  // +1
         // 循环 n 次
-        for (int i = 0; i < n; i++) // +1（每轮都执行 i ++）
+        for (int i = 0; i < n; i++) {   // +1（每轮都执行 i ++）
-        {
             Console.WriteLine(0);   // +1
         }
     }
@@ -744,20 +735,16 @@ $$
 === "C#"
 
     ```csharp title=""
-    void algorithm(int n)
+    void algorithm(int n) {
-    {
         int a = 1;  // +0（技巧 1）
         a = a + n;  // +0（技巧 1）
         // +n（技巧 2）
-        for (int i = 0; i < 5 * n + 1; i++)
+        for (int i = 0; i < 5 * n + 1; i++) {
-        {
             Console.WriteLine(0);
         }
         // +n*n（技巧 3）
-        for (int i = 0; i < 2 * n; i++)
+        for (int i = 0; i < 2 * n; i++) {
-        {
+            for (int j = 0; j < n + 1; j++) {
-            for (int j = 0; j < n + 1; j++)
-            {
                 Console.WriteLine(0);
             }
         }

docs/chapter_hashing/hash_map.md

@@ -368,18 +368,15 @@
     ```csharp title="hash_map.cs"
     /* 遍历哈希表 */
     // 遍历键值对 Key->Value
-    foreach (var kv in map)
+    foreach (var kv in map) {
-    {
         Console.WriteLine(kv.Key + " -> " + kv.Value);
     }
     // 单独遍历键 key
-    foreach (int key in map.Keys)
+    foreach (int key in map.Keys) {
-    {
         Console.WriteLine(key);
     }
     // 单独遍历值 value
-    foreach (String val in map.Values)
+    foreach (String val in map.Values) {
-    {
         Console.WriteLine(val);
     }
     ```

docs/chapter_stack_and_queue/queue.md

@@ -212,10 +212,10 @@
     int pop = queue.Dequeue();
     
     /* 获取队列的长度 */
-    int size = queue.Count();
+    int size = queue.Count;
     
     /* 判断队列是否为空 */
-    bool isEmpty = queue.Count() == 0;
+    bool isEmpty = queue.Count == 0;
     ```
 
 === "Swift"

docs/chapter_stack_and_queue/stack.md

@@ -211,10 +211,10 @@
     int pop = stack.Pop();
     
     /* 获取栈的长度 */
-    int size = stack.Count();
+    int size = stack.Count;
     
     /* 判断是否为空 */
-    bool isEmpty = stack.Count()==0;
+    bool isEmpty = stack.Count == 0;
     ```
 
 === "Swift"