CF1364A 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 $ .