Codeforces Round 719 (Div. 3) |
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Finished |

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data structures

hashing

math

*1200

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D. Same Differences

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou 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 $$$t$$$ ($$$1 \le t \le 10^4$$$). Then $$$t$$$ test cases follow.

The first line of each test case contains one integer $$$n$$$ ($$$1 \le n \le 2 \cdot 10^5$$$).

The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$1 \le a_i \le n$$$) — array $$$a$$$.

It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$2 \cdot 10^5$$$.

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

Codeforces (c) Copyright 2010-2024 Mike Mirzayanov

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