A13522. XXXXX

Ehab loves number theory, but for some reason he hates the number $x$ . Given an array $a$ , find the length of its longest subarray such that the sum of its elements isn't divisible by $x$ , or determine that such subarray doesn't exist.

An array $a$ is a subarray of an array $b$ if $a$ can be obtained from $b$ by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.

The first line contains an integer $t$ $(1 \le t \le 5)$ — the number of test cases you need to solve. The description of the test cases follows.

The first line of each test case contains 2 integers $n$ and $x$ ( $1 \le n \le 10^5$ , $1 \le x \le 10^4$ ) — the number of elements in the array $a$ and the number that Ehab hates.

The second line contains $n$ space-separated integers $a_1$ , $a_2$ , $\ldots$ , $a_{n}$ ( $0 \le a_i \le 10^4$ ) — the elements of the array $a$ .

For each testcase, print the length of the longest subarray whose sum isn't divisible by $x$ . If there's no such subarray, print $-1$ .

In the first test case, the subarray $[2,3]$ has sum of elements $5$ , which isn't divisible by $3$ .

In the second test case, the sum of elements of the whole array is $6$ , which isn't divisible by $4$ .

In the third test case, all subarrays have an even sum, so the answer is $-1$ .