Invert Binary Tree"/>
LeetCode226. Invert Binary Tree
文章目录
- 一、题目
- 二、题解
- 2.1 前序遍历版本
- 2.2 中序遍历版本
- 2.3 后序遍历版本
一、题目
Given the root of a binary tree, invert the tree, and return its root.
Example 1:
Input: root = [4,2,7,1,3,6,9]
Output: [4,7,2,9,6,3,1]
Example 2:
Input: root = [2,1,3]
Output: [2,3,1]
Example 3:
Input: root = []
Output: []
Constraints:
The number of nodes in the tree is in the range [0, 100].
-100 <= Node.val <= 100
二、题解
2.1 前序遍历版本
/*** Definition for a binary tree node.* struct TreeNode {* int val;* TreeNode *left;* TreeNode *right;* TreeNode() : val(0), left(nullptr), right(nullptr) {}* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:TreeNode* invertTree(TreeNode* root) {if(root == nullptr) return root;swap(root->left,root->right);invertTree(root->left);invertTree(root->right);return root;}
};
2.2 中序遍历版本
/*** Definition for a binary tree node.* struct TreeNode {* int val;* TreeNode *left;* TreeNode *right;* TreeNode() : val(0), left(nullptr), right(nullptr) {}* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:TreeNode* invertTree(TreeNode* root) {if(root == nullptr) return root;invertTree(root->left);swap(root->left,root->right);invertTree(root->left);return root;}
};
2.3 后序遍历版本
/*** Definition for a binary tree node.* struct TreeNode {* int val;* TreeNode *left;* TreeNode *right;* TreeNode() : val(0), left(nullptr), right(nullptr) {}* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:TreeNode* invertTree(TreeNode* root) {if(root == nullptr) return root;invertTree(root->left);invertTree(root->right);swap(root->left,root->right);return root;}
};
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LeetCode226. Invert Binary Tree
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