给定一个由n个整点构成的凸多边形,求从n个点里任意选不少于3个点组成的所有凸多边形的面积之和,显然整点构成的多边形面积一定是0.5的整数倍,所以题目需要你算出答案的2倍 mod1000000007的值. 1.凸多边形里选出点组成的还是凸多边形. 2.三个点A,B,C构成的三角形,设从原点到他们的向量为fA,fB,fC,那么三角形面积的2倍就是fA×fB+fB×fC+fC×fA. 3.同理k个点(对应向量按逆时针排序为f1,f2,...,fk)构成的多边形面积的倍等于  对于两个在原多边形上的点i…

pid=4454" target="_blank" style="">题目链接:hdu 4454 Stealing a Cake 题目大意:给定一个起始点s,一个圆形.一个矩形.如今从起点開始,移动到圆形再移动到矩形.求最短距离. 解题思路:在圆周上三分就可以.即对角度[0,2*pi]三分.计算点和矩形的距离能够选点和矩形四条边的距离最短值. #include <cstdio> #include <cstring> #incl…

http://acm.hdu.edu.cn/showproblem.php?pid=2134 Problem Description Ice cream took a bronze medal in the Beijing match. Liu sir is very very happy. So he buys a cake for them. kiki is a child who likes eating, so the task of cuting cake was given to k…

King's Cake 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5640 Description It is the king's birthday before the military parade . The ministers prepared a rectangle cake of size n×m(1≤n,m≤10000) . The king plans to cut the cake himself. But he has…

Cut the Cake Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 263    Accepted Submission(s): 113 Problem Description MMM got a big big big cake, and invited all her M friends to eat the cake toge…

King's Cake Problem Description It is the king's birthday before the military parade . The ministers prepared a rectangle cake of size n×m(1≤n,m≤10000) . The king plans to cut the cake himself. But he has a strange habit of cutting cakes. Each time,…

King's Cake Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 736    Accepted Submission(s): 539 Problem Description It is the king's birthday before the military parade . The ministers prepared a…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4762 题目大意:将n个草莓随机放在蛋糕上,草莓被看做是点,然后将蛋糕平均切成m份,求所有草莓在同一块蛋糕上的概率 Sample Input 2 3 3 3 4   Sample Output 1/3 4/27 分析:计算出这个概率公式为:n/(mn-1),m.n最大为20,mn超出了64位,用到大数,用java容易写出 代码如下: import java.math.BigInteger; impor…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4762 题目大意:一个圆形蛋糕,现在要分成M个相同的扇形,有n个草莓,求n个草莓都在同一个扇形上的概率. 算法思路:n个草莓在圆形上有一个最左边的,为了好理解,先把假设草莓有1-n的不同编号.  现在从n个草莓中选出一个编号A的放在最左边(这个最左边可以随便放),得到C(n,1)*1.然后把其余的n-1草莓不分先后的放在A的右边角大小为(360)/m的扇形区域内就可以了. 所以概率为 n/(m^(n-…

Problem Description   It is the king's birthday before the military parade . The ministers prepared a rectangle cake of size n×m(1≤n,m≤10000) . The king plans to cut the cake himself. But he has a strange habit of cutting cakes. Each time, he will cu…