CF1249A.Yet Another Dividing into Teams

You are a coach of a group consisting of $n$ students. The $i$-th student has programming skill $a_i$. All students have distinct programming skills. You want to divide them into teams in such a way that:

• No two students $i$ and $j$ such that $|a_i - a_j| = 1$ belong to the same team (i.e. skills of each pair of students in the same team have the difference strictly greater than $1$);
• the number of teams is the minimum possible.

You have to answer $q$ independent queries.

你是一名由 $n$ 名学生组成的团队的教练。第 $i$ 名学生的编程能力为 $a_i$，所有学生的编程能力互不相同。你需要将他们分组，使得：

• 任意两名学生 $i$ 和 $j$，若满足 $|a_i - a_j| = 1$，则他们不能被分到同一组（即：同一组中任意两名学生的编程能力之差严格大于 $1$）；
• 组的数量尽可能少。

你需要回答 $q$ 个相互独立的查询。

The first line of the input contains one integer $q$ ($1 \le q \le 100$) — the number of queries. Then $q$ queries follow.

The first line of the query contains one integer $n$ ($1 \le n \le 100$) — the number of students in the query. The second line of the query contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 100$, all $a_i$ are distinct), where $a_i$ is the programming skill of the $i$-th student.

输入的第一行包含一个整数 $q$（$1 \le q \le 100$），表示查询次数。随后是 $q$ 次查询。

每次查询的第一行包含一个整数 $n$（$1 \le n \le 100$），表示该次查询中的学生人数。每次查询的第二行包含 $n$ 个整数 $a_1, a_2, \dots, a_n$（$1 \le a_i \le 100$，且所有 $a_i$ 互不相同），其中 $a_i$ 表示第 $i$ 个学生的编程能力值。

For each query, print the answer on it — the minimum number of teams you can form if no two students $i$ and $j$ such that $|a_i - a_j| = 1$ may belong to the same team (i.e. skills of each pair of students in the same team has the difference strictly greater than $1$)

对于每个查询，请输出其答案——即可以组成的最少队伍数量，要求任意两名学生 $i$ 和 $j$ 若满足 $|a_i - a_j| = 1$，则他们不能属于同一支队伍（即同一支队伍中任意两名学生的技能值之差必须严格大于 $1$）。

In the first query of the example, there are $n=4$ students with the skills $a=[2, 10, 1, 20]$. There is only one restriction here: the $1$-st and the $3$-th students can't be in the same team (because of $|a_1 - a_3|=|2-1|=1$). It is possible to divide them into $2$ teams: for example, students $1$, $2$ and $4$ are in the first team and the student $3$ in the second team.

In the second query of the example, there are $n=2$ students with the skills $a=[3, 6]$. It is possible to compose just a single team containing both students.

在示例的第一个查询中，有 $n=4$ 名学生，其技能值为 $a=[2, 10, 1, 20]$。此处仅存在一条限制：第 $1$ 名与第 $3$ 名学生不能分在同一组（因为 $|a_1 - a_3|=|2-1|=1$）。可以将他们分为 $2$ 组：例如，第 $1$、$2$ 和 $4$ 名学生在第一组，第 $3$ 名学生在第二组。

在示例的第二个查询中，有 $n=2$ 名学生，其技能值为 $a=[3, 6]$。可以仅组成一个包含这两名学生的组。