#D8996. Three Blocks Palindrome (easy version)
Three Blocks Palindrome (easy version)
Three Blocks Palindrome (easy version)
The only difference between easy and hard versions is constraints.
You are given a sequence a consisting of n positive integers.
Let's define a three blocks palindrome as the sequence, consisting of at most two distinct elements (let these elements are a and b, a can be equal b) and is as follows: [\underbrace{a, a, ..., a}{x}, \underbrace{b, b, ..., b}{y}, \underbrace{a, a, ..., a}_{x}]. There x, y are integers greater than or equal to 0. For example, sequences [], [2], [1, 1], [1, 2, 1], [1, 2, 2, 1] and [1, 1, 2, 1, 1] are three block palindromes but [1, 2, 3, 2, 1], [1, 2, 1, 2, 1] and [1, 2] are not.
Your task is to choose the maximum by length subsequence of a that is a three blocks palindrome.
You have to answer t independent test cases.
Recall that the sequence t is a a subsequence of the sequence s if t can be derived from s by removing zero or more elements without changing the order of the remaining elements. For example, if s=[1, 2, 1, 3, 1, 2, 1], then possible subsequences are: [1, 1, 1, 1], [3] and [1, 2, 1, 3, 1, 2, 1], but not [3, 2, 3] and [1, 1, 1, 1, 2].
Input
The first line of the input contains one integer t (1 ≤ t ≤ 2000) — the number of test cases. Then t test cases follow.
The first line of the test case contains one integer n (1 ≤ n ≤ 2000) — the length of a. The second line of the test case contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 26), where a_i is the i-th element of a. Note that the maximum value of a_i can be up to 26.
It is guaranteed that the sum of n over all test cases does not exceed 2000 (∑ n ≤ 2000).
Output
For each test case, print the answer — the maximum possible length of some subsequence of a that is a three blocks palindrome.
Example
Input
6 8 1 1 2 2 3 2 1 1 3 1 3 3 4 1 10 10 1 1 26 2 2 1 3 1 1 1
Output
7 2 4 1 1 3
inputFormat
Input
The first line of the input contains one integer t (1 ≤ t ≤ 2000) — the number of test cases. Then t test cases follow.
The first line of the test case contains one integer n (1 ≤ n ≤ 2000) — the length of a. The second line of the test case contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 26), where a_i is the i-th element of a. Note that the maximum value of a_i can be up to 26.
It is guaranteed that the sum of n over all test cases does not exceed 2000 (∑ n ≤ 2000).
outputFormat
Output
For each test case, print the answer — the maximum possible length of some subsequence of a that is a three blocks palindrome.
Example
Input
6 8 1 1 2 2 3 2 1 1 3 1 3 3 4 1 10 10 1 1 26 2 2 1 3 1 1 1
Output
7 2 4 1 1 3
样例
6
8
1 1 2 2 3 2 1 1
3
1 3 3
4
1 10 10 1
1
26
2
2 1
3
1 1 1
7
2
4
1
1
3
</p>