LeetCode-in-Scala.github.io
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:
- The number of nodes in the tree is in the range
[0, 100]. -100 <= Node.val <= 100
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
}
}