// Encodes a tree to a single string.
public string serialize(TreeNode root)
{
//StringBuilder sb = new StringBuilder();
List<string> list = new List<string>();
PreOrder(list, root);
return String.Join(",", list.ToArray());
}
private void PreOrder(List<string> list, TreeNode node)
{
if (node == null)
list.Add("#");
else
{
list.Add(node.val.ToString());
PreOrder(list, node.left);
PreOrder(list, node.right);
}
}
// Decodes your encoded data to tree.
public TreeNode deserialize(string data)
{
string[] list = data.Split(',');
if (list[0] == "#") return null;
TreeNode root = new TreeNode(Int32.Parse(list[0]));
Stack<TreeNode> stack = new Stack<TreeNode>(list.Length/2);
TreeNode ptr = root,node;
int successiveNull = 0;
for (int i = 1; i < list.Length - 1; i++)
{
if (list[i] != "#")
{
node = new TreeNode(Int32.Parse(list[i]));
if (successiveNull==0)
{
ptr.left = node;
stack.Push(ptr);
}else{
ptr.right = node;
successiveNull = 0;
}
ptr = node;
}
else{
successiveNull++;
if (successiveNull!=1)
{
//ptr.right = null;
ptr = stack.Pop();
}
}
}
return root;
}
static void Main(string[] args)
{
TreeNode root = new TreeNode(1);
TreeNode n2 = new TreeNode(2);
TreeNode n3 = new TreeNode(3);
TreeNode n4 = new TreeNode(4);
TreeNode n5 = new TreeNode(5);
root.left = n2;
root.right = n3;
n2.left = n4;
n2.right = n5;
Codec codec = new Codec();
string str = codec.serialize(root);
TreeNode nh = codec.deserialize(str);
}
