226. 翻转二叉树

典型的二叉树翻转,来源于力扣的226题:翻转二叉树

翻转一棵二叉树。

示例:

输入:

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

     4
   /   \
  7     2
 / \   / \
9   6 3   1
/**
 * 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) {
        //先局部翻转,逐层向上,最后达到全局
        if(root == NULL){
            return root;
        }
        TreeNode* left = invertTree(root->left);
        TreeNode* right = invertTree(root->right);
        root->left = right;
        root->right = left;
        return root;
    }
};
posted @ 2020-09-23 15:33  libbin  阅读(158)  评论(0编辑  收藏  举报