fix(csharp): Modify method name to PascalCase, simplify new expression (#840)

* Modify method name to PascalCase(array and linked list)

* Modify method name to PascalCase(backtracking)

* Modify method name to PascalCase(computational complexity)

* Modify method name to PascalCase(divide and conquer)

* Modify method name to PascalCase(dynamic programming)

* Modify method name to PascalCase(graph)

* Modify method name to PascalCase(greedy)

* Modify method name to PascalCase(hashing)

* Modify method name to PascalCase(heap)

* Modify method name to PascalCase(searching)

* Modify method name to PascalCase(sorting)

* Modify method name to PascalCase(stack and queue)

* Modify method name to PascalCase(tree)

* local check

codes/csharp/chapter_dynamic_programming/climbing_stairs_dfs_mem.cs

@@ -8,7 +8,7 @@ namespace hello_algo.chapter_dynamic_programming;
 
 public class climbing_stairs_dfs_mem {
     /* 记忆化搜索 */
-    public int dfs(int i, int[] mem) {
+    public int Dfs(int i, int[] mem) {
         // 已知 dp[1] 和 dp[2] ，返回之
         if (i == 1 || i == 2)
             return i;
@@ -16,24 +16,24 @@ public class climbing_stairs_dfs_mem {
         if (mem[i] != -1)
             return mem[i];
         // dp[i] = dp[i-1] + dp[i-2]
-        int count = dfs(i - 1, mem) + dfs(i - 2, mem);
+        int count = Dfs(i - 1, mem) + Dfs(i - 2, mem);
         // 记录 dp[i]
         mem[i] = count;
         return count;
     }
 
     /* 爬楼梯：记忆化搜索 */
-    public int climbingStairsDFSMem(int n) {
+    public int ClimbingStairsDFSMem(int n) {
         // mem[i] 记录爬到第 i 阶的方案总数，-1 代表无记录
         int[] mem = new int[n + 1];
         Array.Fill(mem, -1);
-        return dfs(n, mem);
+        return Dfs(n, mem);
     }
 
     [Test]
     public void Test() {
         int n = 9;
-        int res = climbingStairsDFSMem(n);
+        int res = ClimbingStairsDFSMem(n);
         Console.WriteLine($"爬 {n} 阶楼梯共有 {res} 种方案");
     }
 }