Initial data commit

Task/Parametric-polymorphism/C-sharp/parametric-polymorphism-1.cs

@@ -0,0 +1,27 @@
+using System;
+
+class BinaryTree<T>
+{
+    public T value;
+    public BinaryTree<T> left;
+    public BinaryTree<T> right;
+
+    public BinaryTree(T value)
+    {
+        this.value = value;
+    }
+
+    public BinaryTree<U> Map<U>(Func<T, U> f)
+    {
+        BinaryTree<U> tree = new BinaryTree<U>(f(this.value));
+        if (this.left != null)
+        {
+            tree.left = this.left.Map(f);
+        }
+        if (this.right != null)
+        {
+            tree.right = this.right.Map(f);
+        }
+        return tree;
+    }
+}

Task/Parametric-polymorphism/C-sharp/parametric-polymorphism-2.cs

@@ -0,0 +1,11 @@
+class Program
+{
+    static void Main(string[] args)
+    {
+        BinaryTree<int> b = new BinaryTree<int>(6);
+        b.left = new BinaryTree<int>(5);
+        b.right = new BinaryTree<int>(7);
+
+        BinaryTree<double> b2 = b.Map(x => x * 0.5);
+    }
+}

Task/Parametric-polymorphism/C-sharp/parametric-polymorphism-3.cs

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+using System;
+
+class BinaryTree<T>
+{
+    public BinaryTree<T> Left { get; }
+    public BinaryTree<T> Right { get; }
+    public T Value { get; }
+
+    public BinaryTree(T value, BinaryTree<T> left = null, BinaryTree<T> right = null)
+    {
+        this.Value = value;
+        this.Left = left;
+        this.Right = right;
+    }
+
+    public BinaryTree<U> Map<U>(Func<T, U> f)
+    {
+        return new BinaryTree<U>(f(this.Value), this.Left?.Map(f), this.Right?.Map(f));
+    }
+
+    public override string ToString()
+    {
+        var sb = new System.Text.StringBuilder();
+        this.ToString(sb, 0);
+        return sb.ToString();
+    }
+
+    private void ToString(System.Text.StringBuilder sb, int depth)
+    {
+        sb.Append(new string('\t', depth));
+        sb.AppendLine(this.Value?.ToString());
+        this.Left?.ToString(sb, depth + 1);
+        this.Right?.ToString(sb, depth + 1);
+    }
+}
+
+static class Program
+{
+    static void Main()
+    {
+        var b = new BinaryTree<int>(6, new BinaryTree<int>(5), new BinaryTree<int>(7));
+
+        BinaryTree<double> b2 = b.Map(x => x * 0.5);
+
+        Console.WriteLine(b);
+        Console.WriteLine(b2);
+    }
+}