Leetcode 226. Invert Binary Tree(easy)

时间:2022-04-21 15:05:22

Invert a binary tree.

     4
/ \
2 7
/ \ / \
1 3 6 9

to

     4
/ \
7 2
/ \ / \
9 6 3 1

Trivia:
This problem was inspired by this original tweet by Max Howell:

Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.

/* 求翻转二叉树,其实就是求二叉树的镜像

*/

/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
if (!root){
return NULL;
}
TreeNode* tmp = root -> left;
root -> left = invertTree(root->right);
root -> right = invertTree(tmp);
return root;
}
};