翻转一棵二叉树。
示例:
输入:
4
/ \
2 7
/ \ / \
1 3 6 9
输出:
4
/ \
7 2
/ \ / \
9 6 3 1
/**
* @param {TreeNode} root
* @return {TreeNode}
*/
var invertTree = function(root) {
if (root === null) {
return null;
}
const temp = root.left;
root.left = root.right;
root.right = temp;
invertTree(root.left);
invertTree(root.right);
return root;
};