Invert Binary Tree

A Leetcode Binary Tree problem.

Problem

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

Soln

TreeNode* invertTree(TreeNode* root) {
  if (root != nullptr){
    root->left = invertTree(root->left);
    root->right = invertTree(root->right);
    TreeNode* temp = root->left;
    root->left = root->right;
    root->right = temp;
  }
  return root;
}