首先将速度相减,变成A在动而B不动,若速度为0则显然永远不会相交. 枚举A的每个点以及B的每条线段,计算这三个点共线的时刻. 将时刻排序,对于每个区间进行三分,用半平面交计算相交面积. 注意特判相交面积为0但是存在交点的情况. 时间复杂度$O(n^4\log^2n)$. #include<cstdio> #include<algorithm> #include<cmath> using namespace std; const int N=200; const doub…

Search GO 说明:输入题号直接进入相应题目,如需搜索含数字的题目,请在关键词前加单引号 Problem ID Title Source AC Submit Y 1000 A+B Problem 10983 18765 Y 1036 [ZJOI2008]树的统计Count 5293 13132 Y 1588 [HNOI2002]营业额统计 5056 13607 1001 [BeiJing2006]狼抓兔子 4526 18386 Y 2002 [Hnoi2010]Bounce 弹飞绵羊 43…

 最小点覆盖数==最大匹配数 Asteroids Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 12678 Accepted: 6904 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <= 500). The grid co…

Asteroids Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 16211   Accepted: 8819 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <= 500). The grid contains K as…

Asteroids! Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 3159    Accepted Submission(s): 2106 Problem Description You're in space.You want to get home.There are asteroids.You don't want to hit…

                                                                  Asteroids Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 20748   Accepted: 11278 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in…

题目很简单,但是需要推到出二分图最大匹配 = 最小覆盖 最小覆盖:证明过程http://blog.sina.com.cn/s/blog_51cea4040100h152.html Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <= 500). The grid contains K astero…

http://poj.org/problem?id=3041 Asteroids Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 17543   Accepted: 9548 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <…

http://poj.org/problem?id=3041 Asteroids Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12601   Accepted: 6849 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <…

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 2664    Accepted Submission(s): 1794 Problem Description You're in space. You want to get home. There are asteroids. You don't want to hit them.…