226.md

Invert Binary Tree

Description

Invert a binary tree.

     4
   /   \
  2     7
 / \   / \
1   3 6   9

to

     4
   /   \
  7     2
 / \   / \
9   6 3   1

Code

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