LeetCode-in-All

226. Invert Binary Tree

Easy

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:

Solution

import com_github_leetcode.TreeNode

/*
 * Definition for a binary tree node.
 * class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {
 *   var value: Int = _value
 *   var left: TreeNode = _left
 *   var right: TreeNode = _right
 * }
 */
object Solution {
    def invertTree(root: TreeNode): TreeNode = {
        if (root == null) {
            return null
        }
        val temp = root.left
        root.left = invertTree(root.right)
        root.right = invertTree(temp)
        root
    }
}