[LeetCode]101 - Symmetric Tree - 判断对称树(easy) - python
problem description:
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).
For example, this binary tree is symmetric:
[1,2,2,4,3,3,4]
But the following is not:
Note:
Bonus points if you could solve it both recursively(递归) and iteratively(迭代).
思路:
判断二叉树是否是平衡树,比如有两个节点码m,n,我们需要比较m的左子节点的值和n的右子节点的值是否相等,同时还要比较m的右子节点的值和n的左子结点的值是否相等,以此类推比较完所有的左右两个节点。我们可以用递归和迭代两种方法来实现,写法不同,但是算法核心都一样。此处用的是递归的方法。
代码: