二叉樹：

1.獲取樹的深度

class Program
{
    static void Main(string[] args)
    {
        Node root = new Node() { Value = 1 };
        Node level21 = new Node() { Value = 2 };
        Node level22 = new Node() { Value = 3 };
        Node level31 = new Node() { Value = 4 };
        Node level32 = new Node() { Value = 5
 
 };
        Node level33 = new Node() { Value = 6 };
        Node level41 = new Node() { Value = 7 };
        Node level51 = new Node() { Value = 8 };

        root.LeftChild = level21;
        root.RightChild = level22;
        level21.LeftChild = level31;
        level22.LeftChild = level32;
        level22.RightChild 
 
= level33;
        level32.RightChild = level41;
        level41.LeftChild = level51;

        int treeDepth = GetTreeDepth(root);
        //int treeDepth = GetTreeDepthByLoop(root);
        Console.WriteLine(treeDepth);
        Console.ReadKey();
    }

    static int GetTreeDepth(Node root)
    {
        
 
if (root == null)
            return 0;

        int leftchilDeepth = GetTreeDepth(root.LeftChild);
        int rightchilDeepth = GetTreeDepth(root.RightChild);

        return leftchilDeepth > rightchilDeepth ? leftchilDeepth + 1 : rightchilDeepth + 1;
    }


    static int GetTreeDepthByLoop(Node root)
    {
        if (root == null)
            return 0;

        int deepth = 1;
        List<Node> list1 = new List<Node>();
        List<Node> list2 = new List<Node>();
        List<Node> temp;

        list1.Add(root);

        while (true)
        {
            foreach (var node in list1)
            {
                if (node.LeftChild != null)
                    list2.Add(node.LeftChild);
                if (node.RightChild != null)
                    list2.Add(node.RightChild);
            }

            if (list2.Count > 0)
                deepth++;
            else
                return deepth;

            list1.Clear();
            temp = list1;
            list1 = list2;
            list2 = temp;
        }
    }
}


#region Tree
class Node
{
    public int Value { get; set; }
    public Node LeftChild { get; set; }
    public Node RightChild { get; set; }
}
#endregion