多叉樹查找

public class NodeTree
{
    public string Value { get; set; }

    public List<NodeTree> ChildTree { get; set; }
}

class Program
{
    static void Main(string[] args) {
        var tree = new NodeTree() {
            Value = "1",
            ChildTree = new List<NodeTree>() {
                new NodeTree(){ Value="1-1",
                    ChildTree =new List<NodeTree>(){
                        new NodeTree() { Value="1-1-1"},
                        new NodeTree() { Value="1-1-2"}
                    }
                },
                new NodeTree(){ Value="1-2",
                    ChildTree =new List<NodeTree>(){
                        new NodeTree() { Value="1-2-1"},
                        new NodeTree() { Value="1-2-2",
                            ChildTree=new List<NodeTree>(){
                                new NodeTree() { Value="1-2-2-1"}
                            }
                        }
                    }
                },
                new NodeTree(){ Value="1-3"}
            }
        };
        var node = SearchNode(tree, "1-3");
        Console.WriteLine(node.Value);

        Console.WriteLine("===================");

        node = SearchNode2(tree, "1-2-1");
        Console.WriteLine(node.Value);

    }

    //深度優先，遞歸
    static NodeTree SearchNode(NodeTree tree, string valueToFind) {
        if (tree.Value == valueToFind) {
            return tree;
        }
        else {
            if (tree.ChildTree != null) {
                foreach (var item in tree.ChildTree) {
                    var temp = SearchNode(item, valueToFind);
                    if (temp != null) return temp;
                }
            }
        }
        return null;
    }

    //堆棧
    static NodeTree SearchNode2(NodeTree rootNode, string valueToFind) {
        var stack = new Stack<NodeTree>(new[] { rootNode });
        while (stack.Any()) {
            var n = stack.Pop();
            if (n.Value == valueToFind) return n;
            if (n.ChildTree != null)
                foreach (var child in n.ChildTree) stack.Push(child);
        }
        return null;
    }
}