LeeCode - 226. Invert Binary Tree(DFS, BFS, Binary Tree, Recursion)*

문제

Given the root of a binary tree, invert the tree, and return its root.

https://leetcode.com/problems/invert-binary-tree/

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: []

풀이

class Solution {
    public TreeNode invertTree(TreeNode root) {
        if(root==null) return root;
    
        TreeNode right = invertTree(root.right);
        TreeNode left = invertTree(root.left);
        root.left = right;
        root.right = left;
        
        return root;
    }
}