像这样人为设定一个时间阈值，达到该值就视为死循环

虽然能够AC但估计会被hack - 只要成功构造一组需要100001分钟以上才能相遇的数据就无了

#define TIMESTAMP_MAX 100000
int timestamp = 0;
......
//主函数里面↓
while (timestamp<=TIMESTAMP_MAX)
{
	movef(); movec();
	if (f.x == c.x && f.y == c.y)
	{
		cout << timestamp/2 << endl;
		return 0;
	}
}
cout << 0;