private int[] GetElement_Two(int[] arry, int target)
    {
        Dictionary<int, int> dict = new Dictionary<int, int>();
      
        for (int i = 0; i < arry.Length; i++)
        {
           dict.Add(i, arry[i]);
        }
        for (int i = 0; i < arry.Length; i++)
        {
            int temp = target - arry[i];
            
            if (dict.ContainsValue(temp))
            {
                //這句程式碼是，根據value 取得 字典中第一次出現的對應鍵
                //記得 using System.Linq;
                var firstKey = dict.FirstOrDefault(q => q.Value == temp).Key;

                return new int[] { i, firstKey};
            }
        }

        throw new IllegalArgumentException("沒有滿足條件的值");
    }