#include <stdio.h>#include <iostream>#include <algorithm>#include <stdlib.h>using namespace std;typedef struct _point{ int x; int y;}_Point;_Point p[1000100];_Point temp[1010];bool cmp(const _Point& point1, const _Point& point2){ if (point1.x == point2.x) { return point1.y > point2.y; } else { return point1.x > point2.x; }}int main(){ int N; scanf("%d", &N); while(N--) { int n; scanf("%d", &n); int nCount = 0; for (int i = 0; i < n; i++) { scanf("%d%d", &temp[i].x, &temp[i].y); } for (int i = 0; i < n; i++) { for (int j = i + 1; j < n; j++) { p[nCount].x = temp[i].x + temp[j].x; p[nCount++].y = temp[i].y + temp[j].y; } } sort(p, p + nCount, cmp); int k = 1; int sum = 0; for (int i = 0; i < nCount; i++) { if (p[i].x == p[i + 1].x && p[i].y == p[i + 1].y) { k++; } else { sum += (k - 1) * k / 2; k = 1; } } printf("%dn", sum); } return 0;}
