CF1157F.Maximum Balanced Circle

There are $n$ people in a row. The height of the $i$-th person is $a_i$. You can choose any subset of these people and try to arrange them into a balanced circle.

A balanced circle is such an order of people that the difference between heights of any adjacent people is no more than $1$. For example, let heights of chosen people be $[a_{i_1}, a_{i_2}, \dots, a_{i_k}]$, where $k$ is the number of people you choose. Then the condition $|a_{i_j} - a_{i_{j + 1}}| \le 1$ should be satisfied for all $j$ from $1$ to $k-1$ and the condition $|a_{i_1} - a_{i_k}| \le 1$ should be also satisfied. $|x|$ means the absolute value of $x$. It is obvious that the circle consisting of one person is balanced.

Your task is to choose the maximum number of people and construct a balanced circle consisting of all chosen people. It is obvious that the circle consisting of one person is balanced so the answer always exists.

有 $n$ 个人排成一列，第 $i$ 个人的身高为 $a_i$。你可以从中任选一个子集，并尝试将所选的人排成一个平衡的环形队列。

一个平衡的环形队列是指：其中任意两个相邻人的身高之差的绝对值不超过 $1$。例如，设所选人员的身高序列为 $[a_{i_1}, a_{i_2}, \dots, a_{i_k}]$，其中 $k$ 为你所选的人数，则需对所有 $j = 1, 2, \dots, k-1$ 满足 $|a_{i_j} - a_{i_{j + 1}}| \le 1$，且还需满足首尾相邻条件 $|a_{i_1} - a_{i_k}| \le 1$。此处 $|x|$ 表示 $x$ 的绝对值。显然，仅含一人的环形队列是平衡的。

你的任务是选出尽可能多的人，并构造一个由所有被选中者组成的平衡环形队列。由于单人环形队列总是平衡的，因此答案一定存在。

The first line of the input contains one integer $n$ ($1 \le n \le 2 \cdot 10^5$) — the number of people.

The second line of the input contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 2 \cdot 10^5$), where $a_i$ is the height of the $i$-th person.

输入的第一行包含一个整数 $n$（$1 \le n \le 2 \cdot 10^5$）—— 表示人数。

输入的第二行包含 $n$ 个整数 $a_1, a_2, \dots, a_n$（$1 \le a_i \le 2 \cdot 10^5$），其中 $a_i$ 表示第 $i$ 个人的身高。

In the first line of the output print $k$ — the number of people in the maximum balanced circle.

In the second line print $k$ integers $res_1, res_2, \dots, res_k$, where $res_j$ is the height of the $j$-th person in the maximum balanced circle. The condition $|res_{j} - res_{j + 1}| \le 1$ should be satisfied for all $j$ from $1$ to $k-1$ and the condition $|res_{1} - res_{k}| \le 1$ should be also satisfied.

在输出的第一行打印 $k$ —— 最大平衡圆圈中的人数。

在第二行打印 $k$ 个整数 $res_1, res_2, \dots, res_k$，其中 $res_j$ 表示最大平衡圆圈中第 $j$ 个人的身高。需满足对所有 $j = 1$ 到 $k-1$，有 $|res_{j} - res_{j + 1}| \le 1$，且还需满足 $|res_{1} - res_{k}| \le 1$。