Add build scripts for C# and

unify the coding style.

docs/chapter_hashing/hash_map.md

@@ -513,60 +513,9 @@ $$
 === "C#"
 
     ```csharp title="array_hash_map.cs"
-    /* 键值对 int->String */
-    class Entry
-    {
-        public int key;
-        public String val;
-        public Entry(int key, String val)
-        {
-            this.key = key;
-            this.val = val;
-        }
-    }
-    
-    /* 基于数组简易实现的哈希表 */
-    class ArrayHashMap
-    {
-        private List<Entry?> bucket;
-        public ArrayHashMap()
-        {
-            // 初始化一个长度为 100 的桶（数组）
-            bucket = new ();
-            for (int i = 0; i < 100; i++)
-            {
-                bucket.Add(null);
-            }
-        }
-        /* 哈希函数 */
-        private int hashFunc(int key)
-        {
-            int index = key % 100;
-            return index;
-        }
-        /* 查询操作 */
-        public String? get(int key)
-        {
-            int index = hashFunc(key);
-            Entry? pair = bucket[index];
-            if (pair == null) return null;
-            return pair.val;
-        }
-        /* 添加操作 */
-        public void put(int key, String val)
-        {
-            Entry pair = new Entry(key, val);
-            int index = hashFunc(key);
-            bucket[index]=pair;
-        }
-        /* 删除操作 */
-        public void remove(int key)
-        {
-            int index = hashFunc(key);
-            // 置为 null ，代表删除
-            bucket[index]=null;
-        }
-    }
+    [class]{Entry}-[func]{}
+
+    [class]{ArrayHashMap}-[func]{}
     ```
 
 === "Swift"