数据结构（三）二叉树

public class Tree(int value)
{
    public int Value { get; set; } = value;
    public Tree? Left { get; set; }
    public Tree? Right { get; set; }
 
    /// <summary>
    /// 先序遍历 自己 -> 左 -> 右
    /// </summary>
    /// <returns></returns>
    public List<int> PreorderTraversal()
    {
        var list = new List<int> { Value };
 
        list.AddRange(Left?.PreorderTraversal() ?? []);
        list.AddRange(Right?.PreorderTraversal() ?? []);
 
        return list;
    }
 
    /// <summary>
    /// 中序遍历 左 -> 自己 -> 右
    /// </summary>
    /// <returns></returns>
    public List<int> InorderTraversal()
    {
        var list = new List<int>();
 
        list.AddRange(Left?.InorderTraversal() ?? []);
        list.Add(Value);
        list.AddRange(Right?.InorderTraversal() ?? []);
 
        return list;
    }
 
    /// <summary>
    /// 后序遍历 左 -> 右 -> 自己
    /// </summary>
    /// <returns></returns>
    public List<int> PostorderTraversal()
    {
        var list = new List<int>();
 
        list.AddRange(Left?.PostorderTraversal() ?? []);
        list.AddRange(Right?.PostorderTraversal() ?? []);
        list.Add(Value);
 
        return list;
    }
}