Leetcode 226. Invert Binary Tree

Invert a binary tree.

代码语言：javascript复制

     4
   /   
  2     7
 /    / 
1   3 6   9

to

代码语言：javascript复制

     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.

将二叉树的左右子树交换，简单没有话说。

代码语言：javascript复制

/**
 * 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 root;
        swap(root->right, root->left);
        invertTree(root->right);
        invertTree(root->left);
        return root;
    }
};

binary google homebrew max tree

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