CF1781B.Going to the Cinema

传统题 时间 2000 ms 内存 256 MiB 5 尝试 1 已通过 1 标签

Going to the Cinema

A company of nn people is planning a visit to the cinema. Every person can either go to the cinema or not. That depends on how many other people will go. Specifically, every person ii said: "I want to go to the cinema if and only if at least aia_i other people will go, not counting myself". That means that person ii will become sad if:

  • they go to the cinema, and strictly less than aia_i other people go; or
  • they don't go to the cinema, and at least aia_i other people go.

In how many ways can a set of people going to the cinema be chosen so that nobody becomes sad?

Input

Each test contains multiple test cases. The first line contains the number of test cases tt (1t1041 \le t \le 10^4). The description of the test cases follows.

Each test case consists of two lines. The first line contains a single integer nn (2n21052 \le n \le 2 \cdot 10^5) — the number of people in the company.

The second line contains nn integers a1,a2,,ana_1, a_2, \ldots, a_n (0ain10 \le a_i \le n - 1) — integers from peoples' claims.

It is guaranteed that the sum of nn over all test cases does not exceed 21052 \cdot 10^5.

Output

For each test case, print a single integer — the number of different ways to choose a set of people going to the cinema so that nobody becomes sad.

Note

In the first test case, both people want to go to the cinema if and only if the other person goes. There are two valid options: either both people go, or neither of them goes. However, if just one of them goes, both will be sad.

In the second test case, everyone has to go to the cinema. In any other case, someone will be sad.

In the third test case, there are three valid options: person number 22 goes to the cinema; or persons with indices 2,3,4,72, 3, 4, 7 go; or all eight people go.

Samples

4
2
1 1
7
0 1 2 3 4 5 6
8
6 0 3 3 6 7 2 7
5
3 0 0 3 3
2
1
3
2

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