(LeetCode OJ) Invert Binary Tree (226]

(LeetCode OJ) Invert Binary Tree (226]

226. Invert Binary Tree

My Submissions QuestionTotal Accepted: 57653 Total Submissions: 136144 Difficulty: Easy

Invert a binary tree.

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

To

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

Trivia:
This problem was too red 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.

Subscribe to see which companies asked this question

Hide Tags Tree

/*** Definition for a binary tree node. * struct TreeNode {* int val; * TreeNode * left; * TreeNode * right; * TreeNode (int x): val (x), left (NULL), right (NULL) {} *}; * // The following are others' algorithms: I was not sure how to write the reverse program based on the given code format. // The backward recursive algorithm: class Solution {public: // reverse the root node and obtain the pointer TreeNode * invertTree (TreeNode * root) of the root node after the flip. {if (root = NULL) {return NULL;} else {// in this way: the bottom layer of the tree is truly swapped first, and then the top layer is reversed TreeNode * newleft = invertTree (root-> right ); treeNode * newright = invertTree (root-> left); root-> left = newleft; root-> right = newright; return root ;}}};