AlgoLounge

Invert Binary Tree

easy

Leetcode 226. Invert Binary Tree

You are given the root of a binary tree `root`. Invert the binary tree and return its root.

Examples

Example 1

Input:  root = [4,2,7,1,3,6,9]

4 4 / \ / \ 2 7 => 7 2 / \ / \ / \ / \ 1 3 6 9 9 6 3 1Output: [4,7,2,9,6,3,1]

Example 2

Input:  root = [2,1,3]

2 2 / \ => / \ 1 3 3 1Output: [2,3,1]

Example 3

Input:  root = []
Output: []

Constraints

  • 0 <= The number of nodes in the tree <= 100
  • -100 <= Node.val <= 100

How the tests work: trees are written as level-order arrays — [1,null,2] is a root 1 with a right child 2. Your function receives real TreeNode objects, and the tree you return is read back into an array.

TypeScript
Loading editor…
List of test cases (10)
Case 1
root = [4,2,7,1,3,6,9]
Case 2
root = [2,1,3]
Case 3
root = []
Case 4
root = [1]
Case 5
root = [1,2]
Case 6
root = [1,null,2]
Case 7
root = [5,3,8,2,4,7,10]
Case 8
root = [1,2,3,4,5,6,7]
Case 9
root = [10,5,15,null,7,12,20]
Case 10
root = [3,9,20,null,null,15,7]