CF1974C Beautiful Triple Pairs
Description
Polycarp was given an array $ a $ of $ n $ integers. He really likes triples of numbers, so for each $ j $ ( $ 1 \le j \le n - 2 $ ) he wrote down a triple of elements $ [a_j, a_{j + 1}, a_{j + 2}] $ .
Polycarp considers a pair of triples $ b $ and $ c $ beautiful if they differ in exactly one position, that is, one of the following conditions is satisfied:
- $ b_1 \ne c_1 $ and $ b_2 = c_2 $ and $ b_3 = c_3 $ ;
- $ b_1 = c_1 $ and $ b_2 \ne c_2 $ and $ b_3 = c_3 $ ;
- $ b_1 = c_1 $ and $ b_2 = c_2 $ and $ b_3 \ne c_3 $ .
Find the number of beautiful pairs of triples among the written triples $ [a_j, a_{j + 1}, a_{j + 2}] $ .
Input Format
The first line contains a single integer $ t $ ( $ 1 \le t \le 10^4 $ ) — the number of test cases.
The first line of each test case contains a single integer $ n $ ( $ 3 \le n \le 2 \cdot 10^5 $ ) — the length 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 10^6 $ ) — the elements of the array.
It is guaranteed that the sum of the values of $ n $ for all test cases in the test does not exceed $ 2 \cdot 10^5 $ .
Output Format
For each test case, output a single integer — the number of beautiful pairs of triples among the pairs of the form $ [a_j, a_{j + 1}, a_{j + 2}] $ .
Note that the answer may not fit into 32-bit data types.
Explanation/Hint
In the first example, $ a = [3, 2, 2, 2, 3] $ , Polycarp will write the following triples:
1. $ [3, 2, 2] $ ;
2. $ [2, 2, 2] $ ;
3. $ [2, 2, 3] $ .
The beautiful pairs are triple $ 1 $ with triple $ 2 $ and triple $ 2 $ with triple $ 3 $ .In the third example, $ a = [1, 2, 3, 2, 2, 3, 4, 2] $ , Polycarp will write the following triples:
1. $ [1, 2, 3] $ ;
2. $ [2, 3, 2] $ ;
3. $ [3, 2, 2] $ ;
4. $ [2, 2, 3] $ ;
5. $ [2, 3, 4] $ ;
6. $ [3, 4, 2] $ ;
The beautiful pairs are triple $ 1 $ with triple $ 4 $ , triple $ 2 $ with triple $ 5 $ , and triple $ 3 $ with triple $ 6 $ .