给你一棵二叉树的根节点 root ，翻转这棵二叉树，并返回其根节点。
func invertTree(root *TreeNode) *TreeNode {
if root == nil {
return nil
}
root.Right, root.Left = root.Left, root.Right
invertTree(root.Right)
invertTree(root.Left)
return root
}
func invertTree(root *TreeNode) *TreeNode {
q := make([]*TreeNode, 0)
q = append(q, root)
for len(q) > 0 {
top := q[len(q) - 1]
q = q[:len(q) - 1]
if top == nil {
continue
}
top.Right, top.Left = top.Left, top.Right
q = append(q, top.Right)
q = append(q, top.Left)
}
return root
}