diff --git a/dependency/algorithm/README.md b/dependency/algorithm/README.md
index fe9624e..1ea7788 100644
--- a/dependency/algorithm/README.md
+++ b/dependency/algorithm/README.md
@@ -247,6 +247,8 @@ int main()
 
 ## THUAI6
 
+### high-ladder
+
 因为今年的对局得分是两局得分之和，所以会出现一定程度的“数值膨胀”，在这里调低了胜者得分权值，同时提高了比赛分差距悬殊阈值和天梯分差距悬殊阈值。同时由于今年得分的上限不好确定，所以负者失分的基础值变为与胜者的得分之差。
 
 ```c++
@@ -330,3 +332,126 @@ mypair<int> cal(mypair<int> orgScore, mypair<int> competitionScore)
 }
 ```
 
+### competition
+
+与天梯得分算法要满足的“枫氏七条”类似，比赛得分算法也要满足“唐氏四律”，分别如下：
+
+1. 两队经过某场比赛的得分变化，应只与该场比赛有关，而与历史积分无关。
+2. 须赋予比赛获胜一方基础得分，哪怕获胜一方的优势非常小。也就是说，哪怕胜利一方仅以微弱优势获胜，也需要拉开胜者与败者的分差。
+3. 胜利一方优势越大，得分理应越高。
+4. 对于一场比赛，胜利一方的得分不能无限大，须控制在一个合理的数值以下。
+
+- 在非平局的情况下，（胜者）天梯得分与双方比赛分差值成正相关，得分函数如下（以x表示得分差值，y表示（胜者）天梯得分，a、b为固定参数）
+
+​											$$y=ax^2(1-0.375\cdot(\tanh(\frac{x}{b}-1)+1))$$
+
+- 在平局情况下，（双方）天梯得分与比赛分成正相关，得分函数如下（以x表示比赛分，y表示（双方）天梯得分，c为固定参数）
+
+​											$$y=cx^2$$
+
+- 不管是哪种情况，都有得分下界，非平局为100，平局为25
+
+```c++
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <cassert>
+using namespace std;
+
+template <typename T>
+using mypair = pair<T, T>;
+double minScore = 100;
+
+double TieScore(double gameScore)
+{
+    const double get = 9e-5;                                                          // 天梯得分权值
+    double deltaScore = 2000.0;                                                       // 订正的幅度，该值越小，则在双方分差较大时，天梯分数改变量越小，整个函数的变化范围大约为0~2*deltaScore
+    double highScore = 6000.0;                                                        // 将highScore设定为较大值，使得correct较小
+    double correct = 1 - 0.375 * (tanh((highScore - deltaScore) / deltaScore) + 1.0); // 一场比赛中，在双方分差较大时，减小天梯分数的改变量
+    cout << "correct: " << correct << endl;
+    int score = round(gameScore * gameScore * get * correct / 4);
+    return score > minScore / 4 ? score : minScore / 4;
+}
+
+double WinScore(double delta, double winnerGameScore) // 根据游戏得分差值，与绝对分数，决定最后的加分
+{
+    assert(delta > 0);
+    const double firstnerGet = 9e-5;                                              // 胜利者天梯得分权值
+    double deltaScore = 2000.0;                                                   // 订正的幅度，该值越小，则在双方分差较大时，天梯分数改变量越小，整个函数的变化范围大约为0~2*deltaScore
+    double correct = 1 - 0.375 * (tanh((delta - deltaScore) / deltaScore) + 1.0); // 一场比赛中，在双方分差较大时，减小天梯分数的改变量
+    cout << "correct: " << correct << endl;
+    int score = round(delta * delta * firstnerGet * correct);
+    return score > minScore ? score : minScore;
+}
+
+// orgScore 是天梯中两队的分数；competitionScore 是这次游戏两队的得分
+mypair<double> cal(mypair<double> orgScore, mypair<double> competitionScore)
+{
+    // 调整顺序，让第一个元素成为获胜者，便于计算
+
+    bool reverse = false; // 记录是否需要调整
+
+    if (competitionScore.first < competitionScore.second)
+    {
+        reverse = true;
+    }
+
+    if (reverse) // 如果需要换，换两者的顺序
+    {
+        swap(competitionScore.first, competitionScore.second);
+        swap(orgScore.first, orgScore.second);
+    }
+
+    double delta = competitionScore.first - competitionScore.second;
+    double addScore;
+    mypair<double> resScore;
+
+    // 先处理平局的情况
+    if (delta == 0)
+    {
+        addScore = TieScore(competitionScore.first);
+        resScore = mypair<double>(orgScore.first + addScore, orgScore.second + addScore);
+    }
+
+    // 再处理有胜负的情况
+    else
+    {
+        addScore = WinScore(delta, competitionScore.first);
+        resScore = mypair<double>(orgScore.first + addScore, orgScore.second);
+    }
+
+    // 如果换过，再换回来
+    if (reverse)
+    {
+        swap(resScore.first, resScore.second);
+    }
+
+    return resScore;
+}
+
+void Print(mypair<double> score)
+{
+    std::cout << "team1: " << score.first << std::endl
+              << "team2: " << score.second << std::endl;
+}
+
+int main()
+{
+    double x, y, t, i = 0;
+    cin >> t;
+    while (i < t)
+    {
+        cout << "----------------------------------------\n";
+        std::cout << "origin score of team 1 and 2: " << std::endl;
+        std::cin >> x >> y;
+        auto ori = mypair<double>(x, y);
+        std::cout << "game score of team 1 and 2: " << std::endl;
+        std::cin >> x >> y;
+        auto sco = mypair<double>(x, y);
+        Print(cal(ori, sco));
+        ++i;
+    }
+    return 0;
+}
+```
+
diff --git a/installer/Installer/Common.cs b/installer/Installer/Common.cs
index 0f3697d..d38059f 100644
--- a/installer/Installer/Common.cs
+++ b/installer/Installer/Common.cs
@@ -10,7 +10,7 @@ namespace starter.viewmodel.common
 {
     public abstract class NotificationObject : INotifyPropertyChanged
     {
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
         ///< summary>
         /// announce notification
         ///  </summary>
@@ -25,21 +25,21 @@ namespace starter.viewmodel.common
     ///  </summary>
     public class BaseCommand : ICommand
     {
-        private Func<object, bool> _canExecute;
-        private Action<object> _execute;
+        private Func<object?, bool>? _canExecute;
+        private Action<object?> _execute;
 
-        public BaseCommand(Func<object, bool> canExecute, Action<object> execute)
+        public BaseCommand(Func<object?, bool>? canExecute, Action<object?> execute)
         {
             _canExecute = canExecute;
             _execute = execute;
         }
 
-        public BaseCommand(Action<object> execute) :
+        public BaseCommand(Action<object?> execute) :
             this(null, execute)
         {
         }
 
-        public event EventHandler CanExecuteChanged
+        public event EventHandler? CanExecuteChanged
         {
             add
             {
@@ -57,12 +57,12 @@ namespace starter.viewmodel.common
             }
         }
 
-        public bool CanExecute(object parameter)
+        public bool CanExecute(object? parameter)
         {
             return _canExecute == null ? true : _canExecute(parameter);
         }
 
-        public void Execute(object parameter)
+        public void Execute(object? parameter)
         {
             if (_execute != null && CanExecute(parameter))
             {
@@ -79,15 +79,15 @@ namespace starter.viewmodel.common
             {
                 return false;
             }
-            string checkvalue = value.ToString();
-            string targetvalue = parameter.ToString();
+            string checkvalue = value.ToString() ?? "";
+            string targetvalue = parameter.ToString() ?? "";
             bool r = checkvalue.Equals(targetvalue);
             return r;
         }
 
-        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
         {
-            if (value == null || parameter == null)
+            if (value is null || parameter is null)
             {
                 return null;
             }
@@ -132,22 +132,22 @@ namespace starter.viewmodel.common
         static bool _isUpdating = false;
         private static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
-            PasswordBox pb = d as PasswordBox;
+            PasswordBox pb = (d as PasswordBox)!;
             pb.PasswordChanged -= Pb_PasswordChanged;
             if (!_isUpdating)
-                (d as PasswordBox).Password = e.NewValue.ToString();
+                (d as PasswordBox)!.Password = e.NewValue.ToString();
             pb.PasswordChanged += Pb_PasswordChanged;
         }
 
         private static void OnAttachChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
-            PasswordBox pb = d as PasswordBox;
+            PasswordBox pb = (d as PasswordBox)!;
             pb.PasswordChanged += Pb_PasswordChanged;
         }
 
         private static void Pb_PasswordChanged(object sender, RoutedEventArgs e)
         {
-            PasswordBox pb = sender as PasswordBox;
+            PasswordBox pb = (sender as PasswordBox)!;
             _isUpdating = true;
             SetPassword(pb, pb.Password);
             _isUpdating = false;
diff --git a/installer/Installer/MainWindow.xaml b/installer/Installer/MainWindow.xaml
index c29b75d..85f52ab 100644
--- a/installer/Installer/MainWindow.xaml
+++ b/installer/Installer/MainWindow.xaml
@@ -5,7 +5,9 @@
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:Installer" xmlns:c="clr-namespace:starter.viewmodel.common"
         mc:Ignorable="d"
-        Title="Installer" Window.SizeToContent="WidthAndHeight">
+        Title="Installer" Window.SizeToContent="WidthAndHeight"
+        ResizeMode="CanMinimize"
+        >
     <Window.Resources>
         <c:RadioConverter x:Key="RadioConverter"/>
     </Window.Resources>
diff --git a/installer/Installer/Model.cs b/installer/Installer/Model.cs
index f9bea79..552c8cd 100644
--- a/installer/Installer/Model.cs
+++ b/installer/Installer/Model.cs
@@ -21,7 +21,6 @@ using System.Net.Http;
 using System.Windows;
 using System.Windows.Shapes;
 //using System.Windows.Forms;
-using System.Threading.Tasks;
 using System.Threading;
 
 using MessageBox = System.Windows.MessageBox;
@@ -153,18 +152,22 @@ namespace starter.viewmodel.settings
         }
         public bool RecallUser()
         {
-            Username = Web.ReadJson("email");
-            if (Username == null || Username.Equals(""))
+            var username = Web.ReadJson("email");
+            if (username == null || username.Equals(""))
             {
                 Username = "";
                 return false;
             }
-            Password = Web.ReadJson("password");
-            if (Password == null || Username.Equals(""))
+            Username = username;
+
+            var password = Web.ReadJson("password");
+            if (password == null || password.Equals(""))
             {
                 Password = "";
                 return false;
             }
+            Password = password;
+
             return true;
         }
         public bool ForgetUser()
@@ -210,8 +213,6 @@ namespace starter.viewmodel.settings
             switch (CodeRoute.Substring(CodeRoute.LastIndexOf('.') + 1))
             {
                 case "cpp":
-                    Language = "cpp";
-                    break;
                 case "h":
                     Language = "cpp";
                     break;
@@ -244,15 +245,12 @@ namespace starter.viewmodel.settings
         }
         public UsingOS ReadUsingOS()
         {
-            string OS = Web.ReadJson("OS");
-            if (OS == null)
-                return UsingOS.Win;
-            else if (OS.Equals("linux"))
-                return UsingOS.Linux;
-            else if (OS.Equals("osx"))
-                return UsingOS.OSX;
-            else
-                return UsingOS.Win;
+            return Web.ReadJson("OS") switch
+            {
+                "linux" => UsingOS.Linux,
+                "osx" => UsingOS.OSX,
+                _ => UsingOS.Win,
+            };
         }
         /// <summary>
         /// Route of files
@@ -274,7 +272,7 @@ namespace starter.viewmodel.settings
         {
             get; set;
         }
-        public string Language
+        public string? Language
         {
             get; set;
         }
@@ -411,7 +409,7 @@ namespace Downloader
                         {
                             json += @"{""THUAI6""" + ":" + @"""2023""}";
                         }
-                        dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                        dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                         if (dict != null && dict.ContainsKey("installpath"))
                         {
                             FilePath = dict["installpath"].Replace('\\', '/');
@@ -425,11 +423,12 @@ namespace Downloader
                 }
                 else
                 {
-                    FilePath = System.IO.Path.GetDirectoryName(@path);
+                    FilePath = System.IO.Path.GetDirectoryName(@path)
+                        ?? throw new Exception("Fail to find the path of the file");
 
                     //将dat文件写入程序运行路径
                     string json;
-                    Dictionary<string, string> dict = new Dictionary<string, string>();
+                    Dictionary<string, string>? dict;
                     using FileStream fs = new FileStream(Data.path, FileMode.Create, FileAccess.ReadWrite);
                     using (StreamReader r = new StreamReader(fs))
                     {
@@ -438,7 +437,7 @@ namespace Downloader
                         {
                             json += @"{""THUAI6""" + ":" + @"""2023""}";
                         }
-                        dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                        dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                         dict?.Add("installpath", path);
                     }
                     using FileStream fs2 = new FileStream(Data.path, FileMode.Create, FileAccess.ReadWrite);
@@ -451,7 +450,7 @@ namespace Downloader
             public static void ResetFilepath(string newPath)
             {
                 string json;
-                Dictionary<string, string> dict = new Dictionary<string, string>();
+                Dictionary<string, string>? dict;
                 FilePath = newPath.Replace('\\', '/');
                 path = System.IO.Path.Combine(dataPath, "THUAI6.json");
                 using FileStream fs = new FileStream(Data.path, FileMode.Create, FileAccess.ReadWrite);
@@ -462,14 +461,14 @@ namespace Downloader
                     {
                         json += @"{""THUAI6""" + ":" + @"""2023""}";
                     }
-                    dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                    dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                     if (dict != null && dict.ContainsKey("installpath"))
                     {
                         dict["installpath"] = newPath;
                     }
                     else
                     {
-                        dict.Add("installpath", newPath);
+                        dict?.Add("installpath", newPath);
                     }
                     if (dict == null || !dict.ContainsKey("download"))
                     {
@@ -517,9 +516,10 @@ namespace Downloader
                 // 创建存储桶
                 try
                 {
-                    string bucket = "thuai6-1314234950";                              // 格式：BucketName-APPID
-                    string localDir = System.IO.Path.GetDirectoryName(download_dir);  // 本地文件夹
-                    string localFileName = System.IO.Path.GetFileName(download_dir);  // 指定本地保存的文件名
+                    string bucket = "thuai6-1314234950";                                // 格式：BucketName-APPID
+                    string localDir = System.IO.Path.GetDirectoryName(download_dir)     // 本地文件夹
+                        ?? throw new Exception("本地文件夹路径获取失败");
+                    string localFileName = System.IO.Path.GetFileName(download_dir);    // 指定本地保存的文件名
                     GetObjectRequest request = new GetObjectRequest(bucket, key, localDir, localFileName);
 
                     Dictionary<string, string> test = request.GetRequestHeaders();
@@ -553,7 +553,7 @@ namespace Downloader
 
             public static string GetFileMd5Hash(string strFileFullPath)
             {
-                FileStream fst = null;
+                FileStream? fst = null;
                 try
                 {
                     fst = new FileStream(strFileFullPath, FileMode.Open, FileAccess.Read);
@@ -634,7 +634,7 @@ namespace Downloader
                 using (StreamReader r = new StreamReader(System.IO.Path.Combine(Data.FilePath, jsonName)))
                     json = r.ReadToEnd();
                 json = json.Replace("\r", string.Empty).Replace("\n", string.Empty);
-                Dictionary<string, string> jsonDict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                Dictionary<string, string> jsonDict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                 string updatingFolder = "";
                 switch (OS)
                 {
@@ -815,7 +815,7 @@ namespace Downloader
                     {
                         json += @"{""THUAI6""" + ":" + @"""2023""}";
                     }
-                    var dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                    var dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                     if (dict == null || !dict.ContainsKey("download") || "false" == dict["download"])
                     {
                         return false;
@@ -865,15 +865,15 @@ namespace Downloader
                 using (StreamReader r = new StreamReader(System.IO.Path.Combine(Data.FilePath, jsonName)))
                     json = r.ReadToEnd();
                 json = json.Replace("\r", string.Empty).Replace("\n", string.Empty);
-                Dictionary<string, string> jsonDict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                Dictionary<string, string> jsonDict = Utils.DeserializeJson<Dictionary<string, string>>(json);
 
                 newFileName.Clear();
                 updateFileName.Clear();
                 newFileName.Add("THUAI6.tar.gz");
                 Download();
-                Stream inStream = null;
-                Stream gzipStream = null;
-                TarArchive tarArchive = null;
+                Stream? inStream = null;
+                Stream? gzipStream = null;
+                TarArchive? tarArchive = null;
                 try
                 {
                     using (inStream = File.OpenRead(System.IO.Path.Combine(Data.FilePath, "THUAI6.tar.gz")))
@@ -886,7 +886,7 @@ namespace Downloader
                         }
                     }
                 }
-                catch (Exception ex)
+                catch
                 {
                     //出错
                 }
@@ -909,7 +909,7 @@ namespace Downloader
                     {
                         json2 += @"{""THUAI6""" + ":" + @"""2023""}";
                     }
-                    dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json2);
+                    dict = Utils.DeserializeJson<Dictionary<string, string>>(json2);
                     if (dict == null || !dict.ContainsKey("download"))
                     {
                         dict?.Add("download", "true");
@@ -1000,7 +1000,7 @@ namespace Downloader
                         using (StreamReader r = new StreamReader(System.IO.Path.Combine(Data.FilePath, "hash.json")))
                             json = r.ReadToEnd();
                         json = json.Replace("\r", string.Empty).Replace("\n", string.Empty).Replace("/", @"\\");
-                        Dictionary<string, string> jsonDict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                        Dictionary<string, string> jsonDict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                         Change_all_hash(Data.FilePath, jsonDict);
                         OverwriteHash(jsonDict);
                         break;
@@ -1008,7 +1008,7 @@ namespace Downloader
                     else
                     {
                         Console.WriteLine("读取路径失败！请重新输入文件路径：");
-                        Data.ResetFilepath(Console.ReadLine());
+                        Data.ResetFilepath(Console.ReadLine() ?? "");
                     }
                 }
             }
@@ -1068,7 +1068,7 @@ namespace Downloader
                     {
                         json2 += @"{""THUAI6""" + ":" + @"""2023""}";
                     }
-                    dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json2);
+                    dict = Utils.DeserializeJson<Dictionary<string, string>>(json2);
                     if (dict == null || !dict.ContainsKey("download"))
                     {
                         dict?.Add("download", "false");
@@ -1189,7 +1189,7 @@ namespace Downloader
                 while (true)
                 {
                     Console.WriteLine($"1. 更新hash.json   2. 检查更新   3.下载{ProgramName}  4.删除{ProgramName}  5.启动进程  6.移动{ProgramName}到其它路径");
-                    string choose = Console.ReadLine();
+                    string choose = Console.ReadLine() ?? "";
                     if (choose == "1")
                     {
                         if (!CheckAlreadyDownload())
@@ -1216,7 +1216,7 @@ namespace Downloader
                             else
                             {
                                 Console.WriteLine("读取路径失败！请重新输入文件路径：");
-                                Data.ResetFilepath(Console.ReadLine());
+                                Data.ResetFilepath(Console.ReadLine() ?? "");
                             }
                         }
                     }
@@ -1230,7 +1230,7 @@ namespace Downloader
                         {
                             string newpath;
                             Console.WriteLine("请输入下载路径：");
-                            newpath = Console.ReadLine();
+                            newpath = Console.ReadLine() ?? "";
                             Data.ResetFilepath(newpath);
                             DownloadAll();
                         }
@@ -1253,15 +1253,15 @@ namespace Downloader
                     else if (choose == "6")
                     {
                         string newPath;
-                        newPath = Console.ReadLine();
+                        newPath = Console.ReadLine() ?? "";
                         MoveProgram(newPath);
                     }
                     else if (choose == "7")
                     {
                         Console.WriteLine("请输入email：");
-                        string username = Console.ReadLine();
+                        string username = Console.ReadLine() ?? "";
                         Console.WriteLine("请输入密码：");
-                        string password = Console.ReadLine();
+                        string password = Console.ReadLine() ?? "";
 
                         await web.LoginToEEsast(client, username, password);
                     }
@@ -1285,7 +1285,8 @@ namespace Downloader
                 string keyHead = "Installer/";
                 Tencent_cos_download downloader = new Tencent_cos_download();
                 string hashName = "installerHash.json";
-                string dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);
+                string dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule?.FileName)
+                    ?? throw new Exception("Failed to get current directory");
                 int result = 0;
                 try
                 {
@@ -1301,7 +1302,7 @@ namespace Downloader
                 using (StreamReader r = new StreamReader(System.IO.Path.Combine(dir, hashName)))
                     json = r.ReadToEnd();
                 json = json.Replace("\r", string.Empty).Replace("\n", string.Empty);
-                Dictionary<string, string> jsonDict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                Dictionary<string, string> jsonDict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                 string md5 = "";
                 List<string> awaitUpdate = new List<string>();
                 if (jsonDict != null)
@@ -1343,7 +1344,8 @@ namespace Downloader
             static public bool SelfUpdateDismissed()
             {
                 string json;
-                string dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);
+                string dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule?.FileName)
+                    ?? throw new Exception("Failed to get directory!");
                 if (!File.Exists(System.IO.Path.Combine(dir, "updateList.json")))
                     return false;
                 using (StreamReader r = new StreamReader(System.IO.Path.Combine(dir, "updateList.json")))
@@ -1351,7 +1353,7 @@ namespace Downloader
                 json = json.Replace("\r", string.Empty).Replace("\n", string.Empty);
                 List<string> jsonList;
                 if (json != null)
-                    jsonList = JsonConvert.DeserializeObject<List<string>>(json);
+                    jsonList = Utils.DeserializeJson<List<string>>(json);
                 else
                     return false;
                 if (jsonList != null && jsonList.Contains("Dismiss"))
@@ -1403,7 +1405,7 @@ namespace WebConnect
                                     throw new Exception("no token!");
                             logintoken = token;
                             SaveToken();
-                            var info = JsonConvert.DeserializeObject<Dictionary<string, string>>(await response.Content.ReadAsStringAsync());
+                            var info = Utils.DeserializeJson<Dictionary<string, string>>(await response.Content.ReadAsStringAsync());
                             Downloader.UserInfo._id = info["_id"];
                             Downloader.UserInfo.email = info["email"];
                             break;
@@ -1459,7 +1461,7 @@ namespace WebConnect
                     {
                         case System.Net.HttpStatusCode.OK:
 
-                            var res = JsonConvert.DeserializeObject<Dictionary<string, string>>(await response.Content.ReadAsStringAsync());
+                            var res = Utils.DeserializeJson<Dictionary<string, string>>(await response.Content.ReadAsStringAsync());
                             string appid = "1255334966";   // 设置腾讯云账户的账户标识（APPID）
                             string region = "ap-beijing";  // 设置一个默认的存储桶地域
                             CosXmlConfig config = new CosXmlConfig.Builder()
@@ -1584,12 +1586,12 @@ namespace WebConnect
                     {
                         json += @"{""THUAI6""" + ":" + @"""2023""}";
                     }
-                    dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                    dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                     if (dict.ContainsKey("token"))
                     {
                         dict.Remove("token");
                     }
-                    dict?.Add("token", logintoken);
+                    dict.Add("token", logintoken);
                 }
                 using FileStream fs2 = new FileStream(savepath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
                 using StreamWriter sw = new StreamWriter(fs2);
@@ -1627,7 +1629,7 @@ namespace WebConnect
                     json += @"{""THUAI6""" + ":" + @"""2023""}";
                 }
                 Dictionary<string, string> dict = new Dictionary<string, string>();
-                dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                 if (!dict.ContainsKey(key))
                 {
                     dict.Add(key, data);
@@ -1651,7 +1653,7 @@ namespace WebConnect
             }
         }
 
-        public static string ReadJson(string key)
+        public static string? ReadJson(string key)
         {
             try
             {
@@ -1664,7 +1666,7 @@ namespace WebConnect
                 {
                     json += @"{""THUAI6""" + ":" + @"""2023""}";
                 }
-                dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                 fs.Close();
                 sr.Close();
                 return dict[key];
@@ -1691,7 +1693,7 @@ namespace WebConnect
                 {
                     json += @"{""THUAI6""" + ":" + @"""2023""}";
                 }
-                dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
+                dict = Utils.DeserializeJson<Dictionary<string, string>>(json);
                 if (!dict.ContainsKey("token"))
                 {
                     return false;
@@ -1745,9 +1747,9 @@ namespace WebConnect
             var response = await client.SendAsync(request);
             response.EnsureSuccessStatusCode();
             var info = await response.Content.ReadAsStringAsync();
-            var s1 = JsonConvert.DeserializeObject<Dictionary<string, object>>(info)["data"];
-            var s2 = JsonConvert.DeserializeObject<Dictionary<string, List<object>>>(s1.ToString())["contest_team_member"];
-            var sres = JsonConvert.DeserializeObject<Dictionary<string, string>>(s2[0].ToString())["team_id"];
+            var s1 = Utils.DeserializeJson<Dictionary<string, object>>(info)["data"];
+            var s2 = Utils.DeserializeJson<Dictionary<string, List<object>>>(s1.ToString() ?? "")["contest_team_member"];
+            var sres = Utils.DeserializeJson<Dictionary<string, string>>(s2[0].ToString() ?? "")["team_id"];
             return sres;
         }
         async public Task<string> GetUserId(string learnNumber)
@@ -1773,4 +1775,13 @@ namespace WebConnect
         public string Token { get; set; } = "";
     }
 
+    internal static class Utils
+    {
+        public static T DeserializeJson<T>(string json)
+        {
+            return JsonConvert.DeserializeObject<T>(json)
+                ?? throw new Exception("Failed to deserialize json.");
+        }
+    }
+
 }
diff --git a/installer/Installer/ViewModel.cs b/installer/Installer/ViewModel.cs
index ca84add..742fbb1 100644
--- a/installer/Installer/ViewModel.cs
+++ b/installer/Installer/ViewModel.cs
@@ -36,14 +36,15 @@ namespace starter.viewmodel.settings
             //Program.Tencent_cos_download.UpdateHash();
 
             Status = SettingsModel.Status.working;
-            string CurrentDirectory = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);
+            string currentDirectory = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule?.FileName)
+                ?? throw new Exception("Fail to get current directory");
             //MessageBox.Show("更新器工作正常");
             if (!Program.Tencent_cos_download.SelfUpdateDismissed())
             {
                 switch (Program.Tencent_cos_download.CheckSelfVersion())
                 {
                     case 1:
-                        Process.Start(System.IO.Path.Combine(CurrentDirectory, "InstallerUpdater.exe"));
+                        Process.Start(System.IO.Path.Combine(currentDirectory, "InstallerUpdater.exe"));
                         Environment.Exit(0);
                         break;
                     case -1:
@@ -156,7 +157,7 @@ namespace starter.viewmodel.settings
             {
                 e.Cancel = true;
                 MessageBox.Show("下载取消");
-                if (e.Argument.ToString().Equals("Manual"))
+                if (e.Argument?.ToString()?.Equals("Manual") ?? false)
                 {
                     Status = SettingsModel.Status.menu;
                 }
@@ -167,7 +168,7 @@ namespace starter.viewmodel.settings
             else
             {
                 if (obj.Update())
-                    if (e.Argument.ToString().Equals("Manual"))
+                    if (e.Argument?.ToString()?.Equals("Manual") ?? false)
                     {
                         e.Result = 1;
                     }
@@ -598,14 +599,14 @@ namespace starter.viewmodel.settings
             return "";
         }
 
-        private BaseCommand clickBrowseCommand;
+        private BaseCommand? clickBrowseCommand;
         public BaseCommand ClickBrowseCommand
         {
             get
             {
                 if (clickBrowseCommand == null)
                 {
-                    clickBrowseCommand = new BaseCommand(new Action<object>(o =>
+                    clickBrowseCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         Route = RouteSelectWindow("Folder");
                     }));
@@ -613,14 +614,14 @@ namespace starter.viewmodel.settings
                 return clickBrowseCommand;
             }
         }
-        private BaseCommand clickConfirmCommand;
+        private BaseCommand? clickConfirmCommand;
         public BaseCommand ClickConfirmCommand
         {
             get
             {
                 if (clickConfirmCommand == null)
                 {
-                    clickConfirmCommand = new BaseCommand(new Action<object>(o =>
+                    clickConfirmCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         if (Status == SettingsModel.Status.newUser)
                         {
@@ -672,14 +673,14 @@ namespace starter.viewmodel.settings
                 return clickConfirmCommand;
             }
         }
-        private BaseCommand clickUpdateCommand;
+        private BaseCommand? clickUpdateCommand;
         public BaseCommand ClickUpdateCommand
         {
             get
             {
                 if (clickUpdateCommand == null)
                 {
-                    clickUpdateCommand = new BaseCommand(new Action<object>(o =>
+                    clickUpdateCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         this.RaisePropertyChanged("UpdateInfoVis");
                         if (obj.UpdatePlanned)
@@ -719,14 +720,14 @@ namespace starter.viewmodel.settings
                 return clickUpdateCommand;
             }
         }
-        private BaseCommand clickMoveCommand;
+        private BaseCommand? clickMoveCommand;
         public BaseCommand ClickMoveCommand
         {
             get
             {
                 if (clickMoveCommand == null)
                 {
-                    clickMoveCommand = new BaseCommand(new Action<object>(o =>
+                    clickMoveCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         Status = SettingsModel.Status.move;
                     }));
@@ -734,14 +735,14 @@ namespace starter.viewmodel.settings
                 return clickMoveCommand;
             }
         }
-        private BaseCommand clickUninstCommand;
+        private BaseCommand? clickUninstCommand;
         public BaseCommand ClickUninstCommand
         {
             get
             {
                 if (clickUninstCommand == null)
                 {
-                    clickUninstCommand = new BaseCommand(new Action<object>(o =>
+                    clickUninstCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         UpdateInfoVis = Visibility.Collapsed;
                         this.RaisePropertyChanged("UpdateInfoVis");
@@ -767,14 +768,14 @@ namespace starter.viewmodel.settings
             }
         }
 
-        private BaseCommand clickLoginCommand;
+        private BaseCommand? clickLoginCommand;
         public BaseCommand ClickLoginCommand
         {
             get
             {
                 if (clickLoginCommand == null)
                 {
-                    clickLoginCommand = new BaseCommand(new Action<object>(async o =>
+                    clickLoginCommand = new BaseCommand(new Action<object?>(async o =>
                     {
                         switch (await obj.Login())
                         {
@@ -813,14 +814,14 @@ namespace starter.viewmodel.settings
             }
         }
 
-        private BaseCommand clickLaunchCommand;
+        private BaseCommand? clickLaunchCommand;
         public BaseCommand ClickLaunchCommand
         {
             get
             {
                 if (clickLaunchCommand == null)
                 {
-                    clickLaunchCommand = new BaseCommand(new Action<object>(o =>
+                    clickLaunchCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         if (obj.UpdatePlanned)
                         {
@@ -840,14 +841,14 @@ namespace starter.viewmodel.settings
                 return clickLaunchCommand;
             }
         }
-        private BaseCommand clickEditCommand;
+        private BaseCommand? clickEditCommand;
         public BaseCommand ClickEditCommand
         {
             get
             {
                 if (clickEditCommand == null)
                 {
-                    clickEditCommand = new BaseCommand(new Action<object>(o =>
+                    clickEditCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         Status = SettingsModel.Status.menu;
                         if (obj.UpdatePlanned)
@@ -858,14 +859,14 @@ namespace starter.viewmodel.settings
                 return clickEditCommand;
             }
         }
-        private BaseCommand clickBackCommand;
+        private BaseCommand? clickBackCommand;
         public BaseCommand ClickBackCommand
         {
             get
             {
                 if (clickBackCommand == null)
                 {
-                    clickBackCommand = new BaseCommand(new Action<object>(o =>
+                    clickBackCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         UpdateInfoVis = Visibility.Collapsed;
                         this.RaisePropertyChanged("UpdateInfoVis");
@@ -878,14 +879,14 @@ namespace starter.viewmodel.settings
                 return clickBackCommand;
             }
         }
-        private BaseCommand clickUploadCommand;
+        private BaseCommand? clickUploadCommand;
         public BaseCommand ClickUploadCommand
         {
             get
             {
                 if (clickUploadCommand == null)
                 {
-                    clickUploadCommand = new BaseCommand(new Action<object>(async o =>
+                    clickUploadCommand = new BaseCommand(new Action<object?>(async o =>
                     {
                         if (obj.UploadReady)
                         {
@@ -953,14 +954,14 @@ namespace starter.viewmodel.settings
                 return clickUploadCommand;
             }
         }
-        private BaseCommand clickAboutUploadCommand;
+        private BaseCommand? clickAboutUploadCommand;
         public BaseCommand ClickAboutUploadCommand
         {
             get
             {
                 if (clickAboutUploadCommand == null)
                 {
-                    clickAboutUploadCommand = new BaseCommand(new Action<object>(o =>
+                    clickAboutUploadCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         if (obj.UploadReady)
                         {
@@ -987,14 +988,14 @@ namespace starter.viewmodel.settings
                 return clickAboutUploadCommand;
             }
         }
-        private BaseCommand clickExitCommand;
+        private BaseCommand? clickExitCommand;
         public BaseCommand ClickExitCommand
         {
             get
             {
                 if (clickExitCommand == null)
                 {
-                    clickExitCommand = new BaseCommand(new Action<object>(o =>
+                    clickExitCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         Application.Current.Shutdown();
                     }));
@@ -1002,14 +1003,14 @@ namespace starter.viewmodel.settings
                 return clickExitCommand;
             }
         }
-        private BaseCommand clickShiftLanguageCommand;
+        private BaseCommand? clickShiftLanguageCommand;
         public BaseCommand ClickShiftLanguageCommand
         {
             get
             {
                 if (clickShiftLanguageCommand == null)
                 {
-                    clickShiftLanguageCommand = new BaseCommand(new Action<object>(o =>
+                    clickShiftLanguageCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         if (obj.launchLanguage == SettingsModel.LaunchLanguage.cpp)
                             obj.launchLanguage = SettingsModel.LaunchLanguage.python;
@@ -1023,14 +1024,14 @@ namespace starter.viewmodel.settings
                 return clickShiftLanguageCommand;
             }
         }
-        private BaseCommand clickReadCommand;
+        private BaseCommand? clickReadCommand;
         public BaseCommand ClickReadCommand
         {
             get
             {
                 if (clickReadCommand == null)
                 {
-                    clickReadCommand = new BaseCommand(new Action<object>(o =>
+                    clickReadCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         if (!Directory.Exists(Route + "/THUAI6/win"))
                         {
@@ -1050,14 +1051,14 @@ namespace starter.viewmodel.settings
                 return clickReadCommand;
             }
         }
-        private BaseCommand clickSwitchOSCommand;
+        private BaseCommand? clickSwitchOSCommand;
         public BaseCommand ClickSwitchOSCommand
         {
             get
             {
                 if (clickSwitchOSCommand == null)
                 {
-                    clickSwitchOSCommand = new BaseCommand(new Action<object>(o =>
+                    clickSwitchOSCommand = new BaseCommand(new Action<object?>(o =>
                     {
                         switch (obj.usingOS)
                         {
diff --git a/installer/InstallerUpdater/MainWindow.xaml b/installer/InstallerUpdater/MainWindow.xaml
index 271161a..5a3fdf1 100644
--- a/installer/InstallerUpdater/MainWindow.xaml
+++ b/installer/InstallerUpdater/MainWindow.xaml
@@ -5,7 +5,9 @@
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:InstallerUpdater"
         mc:Ignorable="d"
-        Title="MainWindow" Height="180" Width="300">
+        Title="MainWindow" Height="180" Width="300"
+        ResizeMode="CanMinimize"
+        >
     <Grid>
         <Grid.RowDefinitions>
             <RowDefinition Height="40"/>
diff --git a/installer/InstallerUpdater/Program.cs b/installer/InstallerUpdater/Program.cs
index 9a9fced..17e620e 100644
--- a/installer/InstallerUpdater/Program.cs
+++ b/installer/InstallerUpdater/Program.cs
@@ -18,7 +18,8 @@ namespace Program
 {
     class Updater
     {
-        public static string Dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);
+        public static string Dir = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule?.FileName)
+            ?? throw new Exception("Cannot get current directory");
         public static string InstallerName = "Installer.exe";
         public static string jsonKey = "installerHash.json";
         public static string KeyHead = "Installer/";
@@ -31,7 +32,8 @@ namespace Program
                 using (StreamReader r = new StreamReader(System.IO.Path.Combine(Dir, "updateList.json")))
                     json = r.ReadToEnd();
                 json = json.Replace("\r", string.Empty).Replace("\n", string.Empty);
-                List<string> jsonList = JsonConvert.DeserializeObject<List<string>>(json);
+                List<string> jsonList = JsonConvert.DeserializeObject<List<string>>(json)
+                    ?? throw new Exception("Failed to deserialize json!");
                 foreach (string todo in jsonList)
                 {
                     if (!todo.Equals("None"))
@@ -41,14 +43,14 @@ namespace Program
                     }
                 }
             }
-            catch (IOException)
+            catch (IOException ex)
             {
-                MessageBox.Show("下载器本体未能成功关闭");
+                MessageBox.Show($"下载器本体未能成功关闭：\n{ex}");
                 return false;
             }
-            catch
+            catch (Exception ex)
             {
-                MessageBox.Show("尝试下载时出现问题");
+                MessageBox.Show($"尝试下载时出现问题：\n{ex}\n{ex.StackTrace}");
                 return false;
             }
             return true;
@@ -67,7 +69,8 @@ namespace Program
                     json += @"{""None""}";
                 }
                 List<string> ls = new List<string>();
-                ls = JsonConvert.DeserializeObject<List<string>>(json);
+                ls = JsonConvert.DeserializeObject<List<string>>(json)
+                    ?? throw new Exception("Failed to deserialize json!");
                 if (!ls.Contains("Dismiss"))
                 {
                     ls.Add("Dismiss");
@@ -114,9 +117,10 @@ namespace Program
             // 创建存储桶
             try
             {
-                string bucket = "thuai6-1314234950";                              // 格式：BucketName-APPID
-                string localDir = System.IO.Path.GetDirectoryName(download_dir);  // 本地文件夹
-                string localFileName = System.IO.Path.GetFileName(download_dir);  // 指定本地保存的文件名
+                string bucket = "thuai6-1314234950";                                // 格式：BucketName-APPID
+                string localDir = System.IO.Path.GetDirectoryName(download_dir)     // 本地文件夹
+                    ?? throw new Exception("Failed to get directory name!");
+                string localFileName = System.IO.Path.GetFileName(download_dir);    // 指定本地保存的文件名
                 GetObjectRequest request = new GetObjectRequest(bucket, key, localDir, localFileName);
 
                 Dictionary<string, string> test = request.GetRequestHeaders();
diff --git a/logic/Client/Client.csproj b/logic/Client/Client.csproj
index abcb9a6..ffa5629 100644
--- a/logic/Client/Client.csproj
+++ b/logic/Client/Client.csproj
@@ -12,10 +12,6 @@
     <None Remove="Logo.png" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Content Include="eesast_software_trans_enlarged.ico" />
-  </ItemGroup>
-
   <ItemGroup>
 	<PackageReference Include="CommandLineParser" Version="2.9.1" />
     <PackageReference Include="FrameRateTask" Version="1.2.0" />
diff --git a/logic/Client/EESASTLogo.png b/logic/Client/EESASTLogo.png
new file mode 100644
index 0000000..efba5b5
Binary files /dev/null and b/logic/Client/EESASTLogo.png differ
diff --git a/logic/Client/Logo.png b/logic/Client/Logo.png
index efba5b5..6d7d511 100644
Binary files a/logic/Client/Logo.png and b/logic/Client/Logo.png differ
diff --git a/logic/Client/MainWindow.xaml b/logic/Client/MainWindow.xaml
index e1326a7..7046f39 100644
--- a/logic/Client/MainWindow.xaml
+++ b/logic/Client/MainWindow.xaml
@@ -51,7 +51,7 @@
                 <TransformGroup>
                     <ScaleTransform/>
                     <SkewTransform/>
-                    <RotateTransform Angle="-0.377"/>
+                    <RotateTransform Angle="0"/>
                     <TranslateTransform/>
                 </TransformGroup>
             </Label.RenderTransform>
diff --git a/logic/Client/MainWindow.xaml.cs b/logic/Client/MainWindow.xaml.cs
index 340fbd4..d8dd6b5 100644
--- a/logic/Client/MainWindow.xaml.cs
+++ b/logic/Client/MainWindow.xaml.cs
@@ -20,6 +20,7 @@ using Playback;
 using CommandLine;
 using Preparation.Utility;
 using Preparation.Interface;
+using System.Diagnostics.CodeAnalysis;
 
 // 目前MainWindow还未复现的功能：
 // private void ClickToSetMode(object sender, RoutedEventArgs e)
@@ -65,6 +66,7 @@ namespace Client
             ReactToCommandline();
         }
 
+        [MemberNotNull(nameof(StatusBarsOfSurvivor), nameof(StatusBarsOfHunter), nameof(StatusBarsOfCircumstance))]
         private void SetStatusBar()
         {
             StatusBarsOfSurvivor = new StatusBarOfSurvivor[4];
@@ -716,29 +718,21 @@ namespace Client
                         isDataFixed[obj.PlayerId] = true;
                     }
                 }
-                if (StatusBarsOfSurvivor != null)
+
+                for (int i = 0; i < GameData.numOfStudent; i++)
                 {
-                    for (int i = 0; i < GameData.numOfStudent; i++)
-                    {
-                        StatusBarsOfSurvivor[i].NewData(totalLife, totalDeath, coolTime);
-                    }
+                    StatusBarsOfSurvivor[i].NewData(totalLife, totalDeath, coolTime);
                 }
-                if (StatusBarsOfHunter != null)
+
+                StatusBarsOfHunter.NewData(totalLife, totalDeath, coolTime);
+
+                for (int i = 0; i < GameData.numOfStudent; i++)
                 {
-                    StatusBarsOfHunter.NewData(totalLife, totalDeath, coolTime);
+                    StatusBarsOfSurvivor[i].SetFontSize(12 * unitFontsize);
                 }
-                // 完成窗口信息更新
-                if (StatusBarsOfSurvivor != null)
-                {
-                    for (int i = 0; i < GameData.numOfStudent; i++)
-                    {
-                        StatusBarsOfSurvivor[i].SetFontSize(12 * unitFontsize);
-                    }
-                }
-                if (StatusBarsOfHunter != null)
-                    StatusBarsOfHunter.SetFontSize(12 * unitFontsize);
-                if (StatusBarsOfCircumstance != null)
-                    StatusBarsOfCircumstance.SetFontSize(12 * unitFontsize);
+
+                StatusBarsOfHunter.SetFontSize(12 * unitFontsize);
+                StatusBarsOfCircumstance.SetFontSize(12 * unitFontsize);
                 if (!isClientStocked)
                 {
                     try
@@ -1054,6 +1048,11 @@ namespace Client
         {
             if (!isPlaybackMode && !isSpectatorMode)
             {
+                if (client is null)
+                {
+                    return;
+                }
+
                 switch (e.Key)
                 {
                     case Key.W:
@@ -1235,6 +1234,10 @@ namespace Client
         {
             if (!isPlaybackMode && !isSpectatorMode)
             {
+                if (client is null)
+                {
+                    return;
+                }
                 if (humanOrButcher && human != null)
                 {
                     AttackMsg msgJ = new()
@@ -1385,7 +1388,7 @@ namespace Client
         // 以下为Mainwindow自定义属性
         private readonly DispatcherTimer timer;  // 定时器
         private long counter;                    // 预留的取时间变量
-        AvailableService.AvailableServiceClient client;
+        AvailableService.AvailableServiceClient? client;
         AsyncServerStreamingCall<MessageToClient>? responseStream;
         private StatusBarOfSurvivor[] StatusBarsOfSurvivor;
         private StatusBarOfHunter StatusBarsOfHunter;