> #include <cstdio>
> #include <cstdlib>
> #include <string>
> #include <set>
> #include <algorithm>
> using namespace std;
> #define F(i,m,n) for (int i = m; i < n; ++i)
> typedef pair<int, int> PII;
> set<PII> lines;
> int x[202], y[202];
> 
> int main() {
> //	freopen("in.txt", "r", stdin);
> 	int dx, dy, N;
> 
> 	while (scanf("%d", &N) == 1) {
> 		lines.clear();
> 		F(i, 0, N) scanf("%d %d", &x[i], &y[i]);
> 		F(i, 0, N-1) F(j, i+1, N) {
> 			dx = x[j] - x[i], dy = y[j] - y[i];
> 			int gcd = __gcd(dx, dy);
> 			dx /= gcd, dy /= gcd;
> 			lines.insert(PII(dx, dy));
> 		}
> 		printf("%lu\n", lines.size());
> 	}
> 
> 	return 0;
> }

• 用G++提交，否则有Compilation Error (0) Hacker_QC 2010-03-16 13:34:21