talya2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BTreeSerializationLib
{
    public class TreeNode
    {
        public TreeNode() { }
        public TreeNode(string value) { Value = value; }
        public TreeNode(string value, TreeNode left, TreeNode right) : this(value) { Left = left; Right = right; }

        public string Value { get; set; }
        public TreeNode Left { get; set; }
        public TreeNode Right { get; set; }

        public String serialize()
        {
            StringBuilder str = new StringBuilder();
            serialize(str, this, new HashSet<TreeNode>());
            return str.ToString();
        }

        private void serialize(StringBuilder str, TreeNode node, HashSet<TreeNode> nodes)
        {
            if(node == null)
            {
                str.Append("null;");
                return;
            }
            if(nodes.Contains(node))
                throw new BTreeSerializationException();

            nodes.Add(node);

            str.Append(node.Value).Append(";");
            serialize(str, node.Left, nodes);
            serialize(str, node.Right, nodes);
        }

        public static TreeNode deSerialize(string serialized)
        {
            if (string.IsNullOrEmpty(serialized) || !serialized.EndsWith(";"))
                throw new BTreeSerializationException();

            string[] vals = serialized.Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);

            Queue<string> q = new Queue<string>(vals);
            TreeNode node = deSerialize(q);

            if(q.Count() > 0)
                throw new BTreeSerializationException();

            return node;
        }

        private static TreeNode deSerialize(Queue<string> vals)
        {
            if (vals.Count == 0)
                throw new BTreeSerializationException();

            string val = vals.Dequeue();
            if (val == "null")
                return null;

            return new TreeNode(val, deSerialize(vals), deSerialize(vals));
        }
    }
}