Welcome to ZOJ
Information
Select Problem
Runs
Ranklist
ZOJ Problem Set - 2496
Parallelogram Counting

Time Limit: 5 Seconds      Memory Limit: 32768 KB

There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these points. In other words, find the number of 4-element subsets of these points that can be written as {A, B, C, D} such that AB || CD, and BC || AD. No four points are in a straight line.

Input Specification

The first line of the input file contains a single integer t (1 <= t <= 10), the number of test cases. It is followed by the input data for each test case.

The first line of each test case contains an integer n (1 <= n <= 1000). Each of the next n lines, contains 2 space-separated integers x and y (the coordinates of a point) with magnitude (absolute value) of no more than 1000000000.

Output Specification

Output should contain t lines.

Line i contains an integer showing the number of the parallelograms as described above for test case i.

Sample Input

2
6
0 0
2 0
4 0
1 1
3 1
5 1
7
-2 -1
8 9
5 7
1 1
4 8
2 0
9 8

Sample Output

5
6


Source: Asia 2004, Tehran (Iran), Sharif Preliminary
Submit    Status