题目：Symmetric Tree
<span style="font-size:18px;">/**LeetCode Symmetric Tree 对称的树 * 思路：判断一棵树是否对称，1.有左子树就要有右子树 *2.除根节点外对称节点值要相同 * 注意：对称后就是左子树的左节点和右子树的右节点比较 * Definition for binary tree * public class TreeNode { *int val; *TreeNode left; *TreeNode right; *TreeNode(int x) { val = x; } * } */package javaTrain;public class Train8 {public boolean isSymmetric(TreeNode root) {if(root == null) return true;if(root.left == null && root.right == null) return true;else if(root.left == null || root.right == null) return false;return help(root.left,root.right);}private boolean help(TreeNode left,TreeNode right){if(left == null && right == null) return true;else if(left == null || right == null) return false;if(left.val == right.val)return help(left.left,right.right ) && help(left.right,right.left);else return false;}}</span>
，生命太过短暂，今天放弃了明天不一定能得到
