Largest Number X Which Occurs X Times

Given an array ‘A’ consisting of ‘N’ integers, you should return the biggest value ‘X’, which occurs in ‘A’ exactly ‘X’ times. If there is no such value, you should return 0.

For example:

In the given array A[] = {1, 2, 2, 3, 3, 3,}  1 has occurred 1 times, 2 has occurred 2 times and 3 has occurred 3 times. So we will return 3 since it is the maximum number.

Input Format :

The first line contains a single integer ‘T’ denoting the number of test cases, then each test case follows.

The first line of each test case contains an integer ‘N’, denoting the number of integers.
The second line of each test case contains ‘N’ space-separated integers.

Output Format :

For each test case, print the highest number ‘X’ which has appeared ‘X’ a number of times.

 Output for each test case will be printed in a separate line.

Note :

You are not required to print anything; it has already been taken care of. Just implement the function.

Constraints :

1 <= N <= 10^5
1<= array[i] <= 10^9

Time limit: 1 sec