View difference between Paste ID: p8uXiYVs and p6wiisL9

 using System;
 using System.Collections.Generic;
 public class Node<T>
 {
     public Node(T value)
     {
         this.Value = value;
         this.Children = new List<Node<T>>();
     }
 
     public T Value { get; set; }
-    public List<Node<T>> Children { get; private set; }
+    public IList<Node<T>> Children { get; private set; }
 
     public void PrintTree()
     {
         Console.WriteLine("Tree");
         this.Print(string.Empty, true);
     }
 
     private void Print(string prefix, bool isTail)
     {
         Console.WriteLine(prefix + (isTail ? "└── " : "├── ") + this.Value);
         for (int i = 0; i < this.Children.Count - 1; i++)
             this.Children[i].Print(prefix + (isTail ? "    " : "│   "), false);
 
         if (this.Children.Count >= 1)
             this.Children[this.Children.Count - 1].Print(prefix + (isTail ? "    " : "│   "), true);
     }
 }