题意:求光在圆内反射n次后第一次返回原点的方案数 如果k和n-1可约分,则表明是循环多次反射方案才返回原点. #include <iostream> #include <cstring> #include <cstdio> using namespace std; int gcd(int x,int y) { if(x%y != 0) return gcd(y,x%y); return y; } int main() { int T,n; scanf("%d&…

WisKey的眼神 Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2059    Accepted Submission(s): 625 Problem Description WisKey的眼镜有500多度,所以眼神不大好,而且他有个习惯,就是走路喜欢看着地(不是为了拣钱哦^_^),所以大家下次碰见他的时候最好主动打下招呼,呵呵.但是…

题目链接: POJ:id=3831" target="_blank">http://poj.org/problem?id=3831 HDU:http://acm.hdu.edu.cn/showproblem.php?pid=3264 Description The city of M is a famous shopping city and its open-air shopping malls are extremely attractive. During the…

http://acm.hdu.edu.cn/showproblem.php?pid=1700 题目大意: 二维平面,一个圆的圆心在原点上.给定圆上的一点A,求另外两点B,C,B.C在圆上,并且三角形ABC的周长是最长的. 解题思路: 我记得小学的时候给出个一个定理,在园里面正多边形的的周长是最长的,这个定理我不会证明. 所以这里是三角形,当三角形为正三角形的时候,周长是最长的. 因为圆心在原点,所以我就向量(x,y)绕原点逆时针旋转120度和顺时针旋转120度.给定的点A可以看成(x,y)向量.…

http://acm.hdu.edu.cn/showproblem.php?pid=1432 题目大意: 2维平面上给定n个点,求一条直线能够穿过点数最多是多少. 解题思路: 因为题目给定的n(1~700),所以枚举,时间复杂度是O(n^3),不会超时. 枚举两个点,然后判断剩下的点是否在这条直线. AC代码: #include<cstdio> struct Point{ int x, y; Point(, ): x(x), y(y){} void scan(){ scanf("%d…

http://acm.hdu.edu.cn/showproblem.php?pid=1392 题目大意: 二维平面给定n个点,用一条最短的绳子将所有的点都围在里面,求绳子的长度. 解题思路: 凸包的模板.凸包有很多的算法.这里用Adrew. 注意这几组测试数据 1 1 1 3 0 0 1 0 2 0 输出数据 0.00 2.00 #include<cmath> #include<cstdio> #include<algorithm> using namespace st…

Special Tetrahedron Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 328    Accepted Submission(s): 130 Problem Description Given n points which are in three-dimensional space(without repetition)…

Lifting the Stone Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5203    Accepted Submission(s): 2155 Problem Description There are many secret openings in the floor which are covered by a big…

You can Solve a Geometry Problem too Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 6932    Accepted Submission(s): 3350 Problem Description Many geometry(几何)problems were designed in the ACM/I…

The E-pang Palace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others)Total Submission(s): 4547    Accepted Submission(s): 2403 Problem Description E-pang Palace was built in Qin dynasty by Emperor Qin Shihuang in Xia…