题解 | #判断二叉树是否对称#
判断二叉树是否对称
http://www.nowcoder.com/practice/1b0b7f371eae4204bc4a7570c84c2de1
二叉树的题向来都是一看就会，一写就废
public class Solution {
/**
*
* @param root TreeNode类
* @return bool布尔型
*/
public boolean isSymmetric (TreeNode root) {
// write code here
return root == null || isSymmetric(root.left,root.right);
}
public boolean isSymmetric(TreeNode left,TreeNode right){
if(left == null && right == null)
return true;
if(left == null || right == null || left.val != right.val)
return false;
return isSymmetric(left.left,right.right) && isSymmetric(left.right,right.left);
}
} 
