using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

public class Tree<K, V>

     where K : class, IComparable<K>

     where V : class

    {

        private Node<K, V> root;

​

        /// <summary>

        /// Searches tree using BFS but the depth of the search

        /// is limited. Level of root is 0.

        /// </summary>

        /// <param name="root">To start the search</param>

        /// <param name="goal"></param>

        /// <param name="depth">Maximum depth of level to search</param>

        /// <returns>Default of V if key is not found</returns>

        public V DepthLimitedSearch(Node<K, V> root, K goal, int depth)

        {

            if (depth == 0 && root.key == goal)

            {

                return root.value;

            }

            else if (depth > 0)

            {

                foreach (var child in root.children)

                {

                    var result = DepthLimitedSearch(child, goal, depth - 1);

                    if (result != default(V))

                    {

                        return result;

                    }

                }

                return default(V);

            }

            else

            {

                return default(V);

            }

        }

​

        public V IterativeDeepeningSearch(K key, int depth)

        {

            for (int currentDepth = 0; currentDepth <= depth; currentDepth++)

            {

                var v = DepthLimitedSearch(root, key, currentDepth);

                if (v != default(V))

                {

                    return v;

                }

            }

            return default(V);

        }

     }

​

        public class Node<K, V>

            where K : class, IComparable<K>

            where V : class

        {

            public K key;

            public V value;

            public Node<K, V>[] children;

        }