在任意树中查找特定元素

Question

在遍历树 DFS 时，我一直在努力寻找元素。下面是我的树实现。它由另一个类的对象填充。我想要的是通过给定的值在树中找到一个元素，我在尝试这样做时遇到了一些实际问题。有没有办法可以向节点添加一些 Key 引用，然后在所有节点中搜索该引用？我非常感谢您的帮助！ :) 谢谢。

public class TreeNode<T>
    {

    private T value;
    private bool hasParent;
    public TreeNode<T> parent;
    private List<TreeNode<T>> children;
    public TreeNode(T value, TreeNode<T> parent)
    {
        this.parent = parent;
        if (value == null)
        {
            throw new ArgumentNullException(
                  "Cannot insert null value!");
        }
        this.value = value;
        this.children = new List<TreeNode<T>>();
    }

    public T Value
    {
        get
        {
            return this.value;
        }
        set
        {
            this.value = value;
        }
    }
    public int ChildrenCount
    {
        get
        {
            return this.children.Count;
        }
    }
       public class Tree<T>
    {
    // The root of the tree
    private TreeNode<T> root;


    public Tree(T value)
    {
        if (value == null)
        {
            throw new ArgumentNullException(
                  "Cannot insert null value!");
        }

        this.root = new TreeNode<T>(value,null);
    }


    public Tree(T value, params Tree<T>[] children)
        : this(value)
    {
        foreach (Tree<T> child in children)
        {
            this.root.AddChild(child.root);
        }
    }

Answer 1

从代码来看，它是如何填充的并不是很明显，但是我对代码进行了一些调整并尝试清理它，以便我们可以实现填充和搜索树。我添加了一些公共属性和方法。

public class Tree<T>
{
    // The root of the tree
    private TreeNode<T> root;


    public Tree(T value)
    {
        if (value == null)
        {
            throw new ArgumentNullException(nameof(value), "Cannot insert null value!");
        }

        root = new TreeNode<T>(value, null);
    }


    public Tree(T value, params Tree<T>[] children)
        : this(value)
    {
        foreach (Tree<T> child in children)
        {
            root.AddChild(child.root);
        }
    }

    public TreeNode<T> Root => root;

    public TreeNode<T> FindByValue(T value) => Root.FindByValue(value);

}


public class TreeNode<T>
{
    public TreeNode(T value, TreeNode<T> parent)
    {
        this.parent = parent;
        if (value == null)
        {
            throw new ArgumentNullException(nameof(parent), "Cannot insert null value!");
        }
        this.value = value;
        children = new List<TreeNode<T>>();
    }


    private T value;
    public TreeNode<T> parent;
    private List<TreeNode<T>> children;


    public T Value
    {
        get { return value; }
        set { this.value = value; }
    }
    public int ChildrenCount => children.Count;

    public TreeNode<T> AddChild(TreeNode<T> child)
    {
        children.Add(child);
        return child;
    }

    public TreeNode<T> AddChild(T value) => AddChild(new TreeNode<T>(value, this));

    public TreeNode<T> FindByValue(T value)
    {
        if (value.Equals(Value))
            return this;

        foreach (var child in children)
        {
            var match = child.FindByValue(value);
            if (match != null)
                return match;
        }
        return null;
    }
}

示例用法：

//create a new tree..
var tree = new Tree<string>("root-item");

//populate the tree with 10 items with 10 sub items
for (int i = 0; i < 10; i++)
{
    var node = tree.Root.AddChild($"item-{i}");
    for (int w = 0; w < 10; w++)
    {
        node.AddChild($"sub-item-{i}-{w}");
    }
}

//find the root node
var findNode = tree.Root.FindByValue("root-item");

//find a sub node item
findNode = tree.FindByValue("sub-item-1-1");