LeetCode | 226. Invert Binary Tree

最新推荐文章于 2021-03-14 15:30:34 发布

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这篇博客介绍了一个编程问题——翻转二叉树，它源于Max Howell的一条推特，该推特揭示了谷歌面试中对于技术实际应用的重视。提供的代码实现了一个使用广度优先搜索来翻转二叉树的算法。

题目：

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.

代码：

/**
 * 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 == NULL)
            return NULL;
		queue<TreeNode*> q;
		q.push(root);
		while(!q.empty())
		{
			TreeNode* cur_node = q.front();
			q.pop();
			if(cur_node->left)
				q.push(cur_node->left);
			if(cur_node->right)
				q.push(cur_node->right);
			TreeNode* tmp = cur_node->right;
			cur_node->right = cur_node->left;
			cur_node->left = tmp;
		}
		return root;
    }
};