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。
输入:root = [4,2,7,1,3,6,9]
输出:[4,7,2,9,6,3,1]
输入:root = [2,1,3]
输出:[2,3,1]
输入:root = []
输出:[]
- 树中节点数目范围在 [0, 100] 内
- -100 <= Node.val <= 100
use std::rc::Rc;
use std::cell::RefCell;
impl Solution {
pub fn invert_tree(root: Option<Rc<RefCell<TreeNode>>>) -> Option<Rc<RefCell<TreeNode>>> {
if let Some(node) = &root {
let mut node = node.borrow_mut();
let left = node.left.take();
let right = node.right.take();
node.right = Self::invert_tree(left);
node.left = Self::invert_tree(right);
}
root
}
}