题目:
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
题解:
class Solution {
public TreeNode invertTree(TreeNode root) {
//边界条件
if (root == null) {
return null;
}
TreeNode tem = root.left;
root.left = root.right;
root.right = tem;
invertTree(root.left);
invertTree(root.right);
return root;
}
}