#D78. Same Differences
Same Differences
Same Differences
You are given an array a of n integers. Count the number of pairs of indices (i, j) such that i < j and a_j - a_i = j - i.
Input
The first line contains one integer t (1 ≤ t ≤ 10^4). Then t test cases follow.
The first line of each test case contains one integer n (1 ≤ n ≤ 2 ⋅ 10^5).
The second line of each test case contains n integers a_1, a_2, …, a_n (1 ≤ a_i ≤ n) — array a.
It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.
Output
For each test case output the number of pairs of indices (i, j) such that i < j and a_j - a_i = j - i.
Example
Input
4 6 3 5 1 4 6 6 3 1 2 3 4 1 3 3 4 6 1 6 3 4 5 6
Output
1 3 3 10
inputFormat
Input
The first line contains one integer t (1 ≤ t ≤ 10^4). Then t test cases follow.
The first line of each test case contains one integer n (1 ≤ n ≤ 2 ⋅ 10^5).
The second line of each test case contains n integers a_1, a_2, …, a_n (1 ≤ a_i ≤ n) — array a.
It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.
outputFormat
Output
For each test case output the number of pairs of indices (i, j) such that i < j and a_j - a_i = j - i.
Example
Input
4 6 3 5 1 4 6 6 3 1 2 3 4 1 3 3 4 6 1 6 3 4 5 6
Output
1 3 3 10
样例
4
6
3 5 1 4 6 6
3
1 2 3
4
1 3 3 4
6
1 6 3 4 5 6
1
3
3
10
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