226. Invert Binary Tree
給定一個二叉樹的根節點，反轉這棵樹，並返回其根節點。
範例 1：
輸入: root = [4,2,7,1,3,6,9]
輸出: [4,7,2,9,6,3,1]
Python
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
if not root:
return None
# Swap the left and right children
root.left, root.right = root.right, root.left
# Recursively invert the left and right subtrees
self.invertTree(root.left)
self.invertTree(root.right)
return root
16.52MB, 34ms
C++
/**
* 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 nullptr;
}
// Swap the left and right children
TreeNode* temp = root->left;
root->left = root->right;
root->right = temp;
// Recursively invert the left and right subtrees
invertTree(root->left);
invertTree(root->right);
return root;
}
};
11.88MB, 5ms
Javascript
/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @return {TreeNode}
*/
var invertTree = function(root) {
if (root === null) {
return null;
}
// Swap the left and right children
const temp = root.left;
root.left = root.right;
root.right = temp;
// Recursively invert the left and right subtrees
invertTree(root.left);
invertTree(root.right);
return root;
};
49.44MB, 54ms
