226.InvertBinaryTree_zhangsl.go

// Source : https://leetcode.com/problems/invert-binary-tree/
// Author : zhangsl
// Date : 2020-08-24
package main

/*****************************************************************************************************
 *
 * Invert a binary tree.
 *
 * Example:
 *
 * Input:
 *
 * 4
 * / \
 * 2 7
 * / \ / \
 * 1 3 6 9
 *
 * Output:
 *
 * 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 f*** off.
 ******************************************************************************************************/

//Definition for a binary tree node.
typeTreeNodestruct {
Valint
Left*TreeNode
Right*TreeNode
}

// 思路双指针，交换当前节点
funcinvertTree(root*TreeNode) *TreeNode {
helper(root, root)
returnroot
}
funchelper(l, r*TreeNode) {
ifl==nil||r==nil {
return
 }

}