用于在C#中遍历树的递归lambda表达式

public static void TraverseTree(TreeNode root, Action<TreeNode> action)
{
    if (root == null) return;

    action(root);
    TraverseTree(root.Left, action);
    TraverseTree(root.Right, action);
}

public static void TraverseTree(TreeNode root, Action<TreeNode> action)
{
    if (root == null) return;

    var stack = new Stack<TreeNode>();
    stack.Push(root);

    while (stack.Count > 0)
    {
        var node = stack.Pop();
        action(node);

        if (node.Right != null) stack.Push(node.Right);
        if (node.Left != null) stack.Push(node.Left);
    }
}