首页 > itarticle > algorithm notes: leetcode#226 invert binary tree

algorithm notes: leetcode#226 invert binary tree

admin 11月 12, 2020 0

Problem

Solution

Analysis

Python implementation

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class :
    def invertTree(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        if not root is None:
            root.left, root.right = root.right, root.left
            self.invertTree(root.left)
            self.invertTree(root.right)
        return root

Java implementation

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class  {
    public TreeNode invertTree(TreeNode root) {
        if(root != null){
            TreeNode t = root.left;
            root.left = root.right;
            root.right = t;
            invertTree(root.left);
            invertTree(root.right);}
        return root;
    }
}

Time complexity

O(N).

Space complexity

O(L).

Links

226. Invert Binary Tree
(中文版) 算法笔记: 力扣#226 翻转二叉树