# Leetcode 101/100 - Symmetric tree / Same tree

`Note`

- Intuitive way is to use
`recursion`

. - There are three situations
- Both are
`null`

, which means left subtree and right subtree are the same. - One of them is null, so it’s false
- Both are not null, then we need recursion, comapre
`val`

first then use`&&`

. Be careful that we need to compare`left.left, right.right`

and`left.right, right.left`

.

- Both are

Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).

**Example**

1 | Input: root = [1,2,2,3,4,4,3] |

1 | /** |