D. Zigzagstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given an array a_1, a_2 \dots a_n. Calculate the number of tuples (i, j, k, l) such that:   1 \le i < j < k < l \le n;  a_i = a_k and a_j = a_l; InputThe first line contains a single integer t (1 \le t \le 100) — the number of test cases.The first line of each test case contains a single integer n (4 \le n \le 3000) — the size of the array a.The second line of each test case contains n integers a_1, a_2, \dots, a_n (1 \le a_i \le n) — the array a.It's guaranteed that the sum of n in one test doesn't exceed 3000.OutputFor each test case, print the number of described tuples.ExampleInput
2
5
2 2 2 2 2
6
1 3 3 1 2 3
Output
5
2
NoteIn the first test case, for any four indices i < j < k < l are valid, so the answer is the number of tuples.In the second test case, there are 2 valid tuples:   (1, 2, 4, 6): a_1 = a_4 and a_2 = a_6;  (1, 3, 4, 6): a_1 = a_4 and a_3 = a_6. 
2
5
2 2 2 2 2
6
1 3 3 1 2 3

5 2 
['brute force', 'combinatorics', 'data structures', 'math', 'two pointers', '*1900']