diff --git a/src/Sudoku.Console/BulkSolver.cs b/src/Sudoku.Console/BulkSolver.cs
index a2e0ad4..71dce6d 100644
--- a/src/Sudoku.Console/BulkSolver.cs
+++ b/src/Sudoku.Console/BulkSolver.cs
@@ -205,12 +205,14 @@ public void Solve(bool quiet = false, bool noSummary = false)
 
                 i++;
 
-                if (i == 4)
+                if (i != 4)
                 {
-                    System.Console.WriteLine();
-
-                    i = 0;
+                    continue;
                 }
+                
+                System.Console.WriteLine();
+
+                i = 0;
             }
 
             if (i > 0)
@@ -263,7 +265,7 @@ private void ShowProgress(int solved, bool noSummary)
         Monitor.Exit(_consoleLock);
     }
 
-    private static void DumpHistory(int[] puzzle, IReadOnlyList<Move> solution, HistoryType historyType)
+    private static void DumpHistory(int[] puzzle, IReadOnlyCollection<Move> solution, HistoryType historyType)
     {
         int yIncrement;
 
diff --git a/src/Sudoku.Console/ConsoleApplication.cs b/src/Sudoku.Console/ConsoleApplication.cs
index 81802f7..a228493 100644
--- a/src/Sudoku.Console/ConsoleApplication.cs
+++ b/src/Sudoku.Console/ConsoleApplication.cs
@@ -254,7 +254,7 @@ private void GeneratePuzzles()
             return;
         }
 
-        if (clues < 17 || clues > 72)
+        if (clues is < 17 or > 72)
         {
             Out("\n Invalid input.");
 
diff --git a/src/Sudoku.Console/ConsoleSolveVisualiser.cs b/src/Sudoku.Console/ConsoleSolveVisualiser.cs
index f792461..8d2a798 100644
--- a/src/Sudoku.Console/ConsoleSolveVisualiser.cs
+++ b/src/Sudoku.Console/ConsoleSolveVisualiser.cs
@@ -111,14 +111,14 @@ private void Run()
             {
                 var key = Out.ReadKey(true).KeyChar;
 
-                if (key is '<' or ',' && _speedIndex > 0)
+                switch (key)
                 {
-                    _speedIndex--;
-                }
-
-                if (key is '>' or '.' && _speedIndex < _speeds.Length - 1)
-                {
-                    _speedIndex++;
+                    case '<' or ',' when _speedIndex > 0:
+                        _speedIndex--;
+                        break;
+                    case '>' or '.' when _speedIndex < _speeds.Length - 1:
+                        _speedIndex++;
+                        break;
                 }
             }
         }
diff --git a/src/Sudoku.Console/FileHelper.cs b/src/Sudoku.Console/FileHelper.cs
index 3c3d9db..7b4a26e 100644
--- a/src/Sudoku.Console/FileHelper.cs
+++ b/src/Sudoku.Console/FileHelper.cs
@@ -18,11 +18,6 @@ public static string GetSupportingFilesPath()
     {
         const string path = "Supporting Files";
 
-        if (Path.Exists(path))
-        {
-            return path;
-        }
-
-        return $"src/Sudoku.Console/{path}";
+        return Path.Exists(path) ? path : $"src/Sudoku.Console/{path}";
     }
 }
\ No newline at end of file
diff --git a/src/Sudoku/Solver.cs b/src/Sudoku/Solver.cs
index 4e6515e..860305e 100644
--- a/src/Sudoku/Solver.cs
+++ b/src/Sudoku/Solver.cs
@@ -64,12 +64,9 @@ public SudokuResult Solve(int[] puzzle)
         {
             stopwatch.Stop();
 
-            if (span.IsValidSudoku())
-            {
-                return new SudokuResult(_workingCopy, true, _steps, stopwatch.Elapsed.TotalMicroseconds, null, null, "Full valid board");
-            }
-
-            return new SudokuResult(_workingCopy, false, _steps, stopwatch.Elapsed.TotalMicroseconds, null, null, "Full invalid board");
+            return span.IsValidSudoku()
+                ? new SudokuResult(_workingCopy, true, _steps, stopwatch.Elapsed.TotalMicroseconds, null, null, "Full valid board") 
+                : new SudokuResult(_workingCopy, false, _steps, stopwatch.Elapsed.TotalMicroseconds, null, null, "Full invalid board");
         }
 
         if (_score > 64)