Java for LeetCode 101 Symmetric Tree
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 / \ / \ 3 4 4 3
But the following is not:
1 / \ 2 2 \ \ 3 3
解题思路:
重载一个isSymmetric判断两棵树是否对称即可,JAVA实现如下:
public boolean isSymmetric(TreeNode root) { if(root==null) return true; return isSymmetric(root.left,root.right); } public boolean isSymmetric(TreeNode left,TreeNode right){ if(left==null||right==null) return left==null&&right==null; if(left.val!=right.val) return false; return(isSymmetric(left.left,right.right)&&isSymmetric(left.right,right.left)); }