Invert Binary (recursive and iterative)

两种做饭 递归相对好做

1. recursive

class Solution {
public:
void swap(TreeNode** left, TreeNode** right)
{
TreeNode* temp = (*left);
*left = *right;
*right = temp;
}
TreeNode* invertTree(TreeNode* root) {

if (root == nullptr)
return root;
invertTree(root->left);
invertTree(root->right);
swap ((&root->left), (&root->right));
return root;

}
};其实核心思想还是 1.左边到底 2.借助程序的stack 自动跳回到上一根结点 然后再左边到底
2. Iterative