0101-symmetric-tree.adoc

101. Symmetric Tree

LeetCode - Symmetric Tree

为什么执行结果显示递归更快？而不是队列呢？

Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).

For example, this binary tree [1,2,2,3,4,4,3] is symmetric:

    1
   / \
  2   2
 / \ / \
3  4 4  3

But the following [1,2,2,null,3,null,3] is not:

    1
   / \
  2   2
   \   \
   3    3

Note:

Bonus points if you could solve it both recursively and iteratively.

link:{sourcedir}/_0101_SymmetricTree.java[role=include]