Initial commit

.gitignore

@@ -0,0 +1,4 @@
+bin
+obj
+.vscode
+.vs

EightQueens.cs

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+namespace EightQueens;
+
+public struct Coord(int x, int y)
+{
+    public int X { get; set; } = x;
+    public int Y { get; set; } = y;
+};
+
+public class Board {
+
+    private List<Coord> Figures {get;set;} = [];
+
+    public bool IsFieldBusy(int x, int y)
+    {
+        return Figures.Any(f => x==f.X && y==f.Y);
+    }
+
+    public void Add(int x, int y)
+    {
+        var pos = new Coord(x, y);
+
+        if (IsFieldBusy(x, y)) return;
+        Figures.Add(pos);
+    }
+
+    public void Remove(int x, int y)
+    {
+        var pos = new Coord(x, y);
+        Figures.Remove(pos);
+    }
+
+    public void Clear()
+    {
+        Figures.Clear();
+    }
+
+    public List<Coord> GetFigures()
+    {
+        return Figures;
+    }
+
+    public void Draw()
+    {
+        for (int x = 0; x < 9; x++)
+        {
+            string row = "";
+            for (int y = 0; y < 9; y++)
+            {
+                if (x + y == 0)
+                {
+                    row += " ";
+                }
+                else if (y == 0)
+                {
+                    row += $"{x}";
+                }
+                else if (x == 0)
+                {
+                    row += $"{y}";
+                }
+                else if (IsFieldBusy(x, y))
+                {
+                    row += "O";
+                }
+                else
+                {
+                    row += "#";
+                }
+                row+=" ";
+            }
+            Console.WriteLine(row);
+        }
+
+    }
+
+    public int Count()
+    {
+        return Figures.Count;
+    }
+
+    public bool IsFieldSafe(int row, int col)
+    {
+        var figs = Figures.Where(f => !(row==f.X && col==f.Y)).ToList();
+
+        foreach (var fig in figs)
+        {
+            if (fig.X == row || fig.Y == col) return false;
+            if (Math.Abs(fig.X - row) == Math.Abs(fig.Y - col)) return false;
+        }
+
+        return true;
+    }
+
+    public bool IsBoardSafe()
+    {
+        foreach (var fig in Figures)
+        {
+            if (!IsFieldSafe(fig.X, fig.Y)) return false;
+        }
+        return true;
+    }
+}

EightQueens.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Program.cs

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+using EightQueens;
+
+var board = new Board();
+
+string[] cmd = [];
+bool quit = false;
+while (!quit)
+{
+    board.Draw();
+    Console.WriteLine(
+      $"Действия:\n"
+    + $"add X Y - добавить ферзя\n"
+    + $"del X Y - удалить ферзя\n"
+    + $"clear - очистить доску\n"
+    + $"issolved - проверить решение задачи\n"
+    + $"exit - выход\n");
+    
+    var cmdString = Console.ReadLine();
+    if (cmdString == null) continue;
+    cmd = cmdString.Trim().Split();
+
+    switch (cmd[0])
+    {
+        case "add":
+            board.Add(int.Parse(cmd[1]), int.Parse(cmd[2]));
+            break;
+        case "del":
+            board.Remove(int.Parse(cmd[1]), int.Parse(cmd[2]));
+            break;
+        case "clear":
+            board.Clear();
+            break;
+        case "issolved":
+            Console.WriteLine(board.IsBoardSafe() ? "Ферзи в безопасности!" : "Задача не выполняется");
+            break;
+        default:
+            Console.WriteLine($"Неизвестная команда '{cmd[0]}'");
+            break;
+    }
+
+    Console.WriteLine($"\n=======================\n");
+}