反向搜索列表列表

Question

I have a list set up in the following manner that I would like to search and manipulate (delete items) in reverse order, but I can't figure out a good way to do this.

Currently, the list is an Observable Collection , but I can change it to another type.

I am able to search down the list using recursion, but how do I search up (starting with the children and working my way up)?

ID, ListOfChildren <>, Name

For example:

ID: 1, ListOfChildren Count = 2, Name = "Room 1"<br>
--- ID 10, ListOfChildren, Count = 0, Name = "Bed 1.1"<br>
--- ID 11, ListOfChildren, Count = 0, Name = "Bed 1.2"<br>

ID: 2, ListOfChildren Count = 2, Name = "Room 2"<br>
--- ID 12, ListOfChildren, Count = 0, Name = "Bed 2.1"<br>
--- ID 13, ListOfChildren, Count = 0, Name = "Bed 2.2"<br>

ID: 3, ListOfChildren Count = 2, Name = "Room 3"<br>
--- ID 14, ListOfChildren, Count = 0, Name = "Bed 3.1"<br>
--- ID 15, ListOfChildren, Count = 0, Name = "Bed 3.2"<br>

Thanks, Bill

Answer 1

You could do the opposite of an in-order search, have the method return wether the child needs to be removed. Rewrote the order to actually be reverse. Or add a reference to the parent in the child, yes that costs extra memory, which is why you almost always have to traverse the tree.

public class Tree
{
    private static Random rand = new Random();
    public List<Tree> Children = new List<Tree>();

    public Tree Parent;

    public string Name;

    public Tree(Tree parent)
    {
        Parent = parent;
        Name = rand.Next(10000).ToString();
    }

    // Removing without tree traversal.
    public void DeleteParent()
    {
        this.Parent.Parent.Children.Remove(this.Parent);
    }

    public bool Remove(string name)
    {
        for(int i = Children.Count - 1; i >= 0; i--)
        {
            if (Children[i].Remove(name))
            {
                // Use a for-loop with index to remove the child right away.
                Children.Remove(Children[i]);
                // Extra remove handling
                i--;
            }
        }

        // Remove condition.
        return this.Name.Contains(name);
    }
}

Does it matter what order this happens? If you delete a parent all it's children will be removed by the memory management.