LeetCode刷题记34-101. 对称二叉树

LeetCode刷题记34

101. 对称二叉树

题目

7/10

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
     
    public boolean isSymmetric(TreeNode root) {
     
        if (root == null) {
     
            return true;
        }
        Queue<TreeNode> q = new LinkedList<TreeNode>();
        q.offer(root.left);
        q.offer(root.right);
        while(q.isEmpty() == false) {
     
            TreeNode n1 = q.poll();
            TreeNode n2 = q.poll();
            if(n1 != null && n2 != null) {
     
                if (n1.val != n2.val) {
     
                    return false;
                }
                q.offer(n1.left);
                q.offer(n2.right);
                q.offer(n1.right);
                q.offer(n2.left);
            } else if (n1 != null || n2 != null) {
     
                return false;
            }
         }
        return true;
    }
}

java里面队列没有push也没有pop，哎我又忘记了
用法
明天一定补上。。。
34/150