1. Remove unused libs.

2. Add file headers.
3. Modify file name to match Java's.
4. Fix some issues.

codes/csharp/chapter_array_and_linkedlist/Array.cs

@@ -1,4 +1,4 @@
-// File: Array.cs
+// File: array.cs
 // Created Time: 2022-12-14
 // Author: mingXta (1195669834@qq.com)
 
@@ -6,7 +6,7 @@ using NUnit.Framework;
 
 namespace hello_algo.chapter_array_and_linkedlist
 {
-    public class Array
+    public class array
     {
         /// <summary>
         /// 随机返回一个数组元素

codes/csharp/chapter_array_and_linkedlist/linked_list.cs

@@ -1,4 +1,4 @@
-// File: LinkedList.cs
+// File: linked_list.cs
 // Created Time: 2022-12-16
 // Author: mingXta (1195669834@qq.com)
 
@@ -7,14 +7,14 @@ using NUnit.Framework;
 
 namespace hello_algo.chapter_array_and_linkedlist
 {
-    public class LinkedList
+    public class linked_list
     {
         /// <summary>
         /// 在链表的结点 n0 之后插入结点 P
         /// </summary>
         public static void Insert(ListNode n0, ListNode P)
         {
-            ListNode n1 = n0.next;
+            ListNode? n1 = n0.next;
             n0.next = P;
             P.next = n1;
         }
@@ -28,7 +28,7 @@ namespace hello_algo.chapter_array_and_linkedlist
                 return;
             // n0 -> P -> n1
             ListNode P = n0.next;
-            ListNode n1 = P.next;
+            ListNode? n1 = P.next;
             n0.next = n1;
         }
 
@@ -78,15 +78,15 @@ namespace hello_algo.chapter_array_and_linkedlist
             n1.next = n2;
             n2.next = n3;
             n3.next = n4;
-            Console.WriteLine($"初始化的链表为{n0}");
+            Console.WriteLine($"初始化的链表为 {n0}");
 
             // 插入结点 
             Insert(n0, new ListNode(0));
-            Console.WriteLine($"插入结点后的链表为{n0}");
+            Console.WriteLine($"插入结点后的链表为 {n0}");
 
             // 删除结点 
             Remove(n0);
-            Console.WriteLine($"删除结点后的链表为{n0}");
+            Console.WriteLine($"删除结点后的链表为 {n0}");
 
             // 访问结点 
             ListNode? node = Access(n0, 3);

codes/csharp/chapter_array_and_linkedlist/list.cs

@@ -1,11 +1,8 @@
-using Newtonsoft.Json.Linq;
+// File: list.cs
+// Created Time: 2022-12-16
+// Author: mingXta (1195669834@qq.com)
+
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using System.Xml.Linq;
 
 namespace hello_algo.chapter_array_and_linkedlist
 {
@@ -46,7 +43,7 @@ namespace hello_algo.chapter_array_and_linkedlist
             Console.WriteLine("在索引 3 处插入数字 6 ，得到 list = " + string.Join(",", list));
 
             /* 删除元素 */
-            list.Remove(3);
+            list.RemoveAt(3);
             Console.WriteLine("删除索引 3 处的元素，得到 list = " + string.Join(",", list));
 
             /* 通过索引遍历列表 */

codes/csharp/chapter_array_and_linkedlist/my_list.cs

@@ -1,10 +1,8 @@
-using Newtonsoft.Json.Linq;
+// File: my_list.cs
+// Created Time: 2022-12-16
+// Author: mingXta (1195669834@qq.com)
+
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace hello_algo.chapter_array_and_linkedlist
 {

codes/csharp/include/ListNode.cs

@@ -10,7 +10,7 @@ namespace hello_algo.include
     public class ListNode
     {
         public int val;
-        public ListNode next;
+        public ListNode? next;
 
         /// <summary>
         /// Generate a linked list with an array
@@ -26,7 +26,7 @@ namespace hello_algo.include
         /// </summary>
         /// <param name="arr"></param>
         /// <returns></returns>
-        public static ListNode ArrToLinkedList(int[] arr)
+        public static ListNode? ArrToLinkedList(int[] arr)
         {
             ListNode dum = new ListNode(0);
             ListNode head = dum;
@@ -44,7 +44,7 @@ namespace hello_algo.include
         /// <param name="head"></param>
         /// <param name="val"></param>
         /// <returns></returns>
-        public static ListNode GetListNode(ListNode head, int val)
+        public static ListNode? GetListNode(ListNode? head, int val)
         {
             while (head != null && head.val != val)
             {

codes/csharp/include/PrintUtil.cs

@@ -1,9 +1,6 @@
-using System;
+// File: ListNode.cs
-using System.Collections.Generic;
+// Created Time: 2022-12-16
-using System.Diagnostics.SymbolStore;
+// Author: mingXta (1195669834@qq.com)
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace hello_algo.include
 {
@@ -21,21 +18,6 @@ namespace hello_algo.include
 
     public class PrintUtil
     {
-        /**
-         * Print a linked list
-         * @param head
-         */
-        public static void printLinkedList(ListNode head)
-        {
-            List<String> list = new();
-            while (head != null)
-            {
-                list.Add(head.val.ToString());
-                head = head.next;
-            }
-            Console.Write(String.Join(" -> ", list));
-        }
-
         /**
          * The interface of the tree printer
          * This tree printer is borrowed from TECHIE DELIGHT
@@ -81,7 +63,7 @@ namespace hello_algo.include
             }
 
             showTrunks(trunk);
-            Console.Write(" " + root.val);
+            Console.WriteLine(" " + root.val);
 
             if (prev != null)
             {

codes/csharp/include/TreeNode.cs

@@ -1,9 +1,13 @@
+// File: ListNode.cs
+// Created Time: 2022-12-16
+// Author: mingXta (1195669834@qq.com)
+
 namespace hello_algo.include
 {
     public class TreeNode
     {
         public int? val;        // 结点值
-        public int height;     // 结点高度
+        public int height;      // 结点高度
         public TreeNode? left;  // 左子结点引用
         public TreeNode? right; // 右子结点引用