题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5120 A ring is a 2-D figure bounded by two circles sharing the common center. The radius for these circles are denoted by r and R (r < R). For more details, refer to the gray part in the illustration bel…

Intersection Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5120 Description Matt is a big fan of logo design. Recently he falls in love with logo made up by rings. The following figures are some famous examples…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5120 解题报告:给你两个完全相同的圆环,要你求这两个圆环相交的部分面积是多少? 题意看了好久没懂.圆环由一个大圆里面套一个小圆,中间部分就是圆环,两圆环相交面积 = 大圆相交的面积 - 2*大圆与小圆相交的面积 + 小圆与小圆相交的面积. 也就是说,这题就可以化为求两个圆的相交的面积了.可以利用两个圆的方程,求出圆的交点所在的直线,然后求出圆心到这条直线的距离,就可以求出两个圆对应的扇形的圆心角是多…

Matt is a big fan of logo design. Recently he falls in love with logo made up by rings. The following figures are some famous examples you may know.A ring is a 2-D figure bounded by two circles sharing the common center. The radius for these circles…

Intersection Time Limit: 4000/4000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others) Problem Description Matt is a big fan of logo design. Recently he falls in love with logo made up by rings. The following figures are some famous examp…

Problem Description Matt is a big fan of logo design. Recently he falls in love with logo made up by rings. The following figures are some famous examples you may know. A ring is a 2-D figure bounded by two circles sharing the common center. The radi…

题意:给定两个圆环,求两个圆环相交的面积. 思路:由于圆心和半径不一样,分了好多种情况,后来发现只要把两个圆相交的函数写好之后就不需要那么复杂了.两个圆相交的面积的模板如下: double area_of_overlap(point c1, double r1, point c2, double r2) { double d = dist(c1, c2); ) ; ) { double r = min(r1, r2); return PI * r * r; } double x = (d * d…

题意:给定两个圆环,求两个圆环的面积交. 析:很容易知道,圆环面积交就是,大圆与大圆面积交 - 大圆和小圆面积交 - 小圆和大圆面积交 + 小圆和小圆面积交. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <cmath> #includ…

Matt is a big fan of logo design. Recently he falls in love with logo made up by rings. The following figures are some famous examples you may know. A ring is a 2-D figure bounded by two circles sharing the common center. The radius for these circles…

题意:有K个棋子在一个大小为N×N的棋盘.一开始,它们都在棋盘的顶端,它们起始的位置是 (1,a1),(1,a2),...,(1,ak) ,它们的目的地是 (n,b1),(n,b2),...,(n,bk). 一个位于 (r,c) 的棋子每一步只能向右走到 (r,c+1) 或者向下走到 (r+1,c) . 我们把 i 棋子从 (1,ai) 走到 (n,bi) 的路径记作 pi . 你的任务是计算有多少种方案把n个棋子送到目的地,并且对于任意两个不同的棋子 i,j ,使得路径 pi 与 pj 不相交…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5112 解题报告:扫一遍 #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<cmath> using namespace std; ; struct node { double t,x; }rec[maxn]; double Max(do…

Intersection Time Limit: 4000/4000 MS (Java/Others) Memory Limit: 512000/512000 K (Java/Others) Total Submission(s): 602 Accepted Submission(s): 247 Problem Description Matt is a big fan of logo design. Recently he falls in love with logo made up by…

题意:求环的相交面积 思路: 通过画图可知,面积= 大圆相交面积 - 大小圆相交面积*2 + 小小圆相交面积  再通过圆相交模板计算即可 #include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include <cmath> using namespace std; typedef long long ll; #define PI 3.14159…

题意:告诉你两个圆环,求圆环相交的面积. /* gyt Live up to every day */ #include<cstdio> #include<cmath> #include<iostream> #include<algorithm> #include<vector> #include<stack> #include<cstring> #include<queue> #include<set&…

两个圆环的内外径相同 给出内外径 和 两个圆心 求两个圆环相交的面积 画下图可以知道 就是两个大圆交-2*小圆与大圆交+2小圆交 Sample Input22 30 00 02 30 05 0 Sample OutputCase #1: 15.707963Case #2: 2.250778 # include <iostream> # include <cstdio> # include <cstring> # include <algorithm> # i…

题目链接 题意 : 给定方格中第一行的各个起点.再给定最后一行与起点相对应的终点.问你从这些起点出发到各自的终点.不相交的路径有多少条.移动方向只能向下或向右 分析 : 首先对于多起点和多终点的不相交路径.有一个LGV定理 实际上就是 n^2 构造矩阵.再计算其行列式 矩阵的构造方法可以看看这个 ==> Click here 那么接下来就是确定各自路径的方案数了 这是一个经典问题 这里需要求解组合数.用预处理阶乘逆元的方法即可求出 #include<bits/stdc++.h> #def…

pid=4873" target="_blank" style="">题目链接:hdu 4873 ZCC Loves Intersection 题目大意:给出N,D,表示在一个D维的坐标上.坐标范围为0~N-1.在这个坐标系中有D条线段,分别平行与各个坐标轴,每秒会依据题目中的伪代码随机生成各个线段的位置.两条直线相交的话会得一分,问每秒得分的期望. 解题思路:总的情况(ND−1∗C(2N))D,两条直线相交的得分C(2D)∗s2∗ND−2∗(ND−…

HDU 4873 ZCC Loves Intersection pid=4873" target="_blank" style="">题目链接 题意:d维的.长度为n的块中,每次选d条平行于各条轴的线段,假设有两两相交则点数加1,问每次得到点数的期望是多少 思路:自己推还是差一些,转篇官方题接把,感觉自己想的没想到把分子那项拆分成几个多项式的和,然后能够转化为公式求解. 代码: #include <cstdio> #include <…

在一个D维空间,只有整点,点的每个维度的值是0~n-1 .现每秒生成D条线段,第i条线段与第i维度的轴平行.问D条线段的相交期望. 生成线段[a1,a2]的方法(假设该线段为第i条,即与第i维度的轴平行)为,i!=j时,a1[j]=a2[j],且随机取区间[0,n-1]内的整数.然后a1[i],a2[i]在保证a1[i]<a2[i]的前提下同样随机. 由于D条线段各自跟自己维度的轴平行,我们可以转换成只求第i个维度与第j个维度的相交期望,然后乘以C(2,n)就好了 显然线段[a1,a2]和线段[…

果然,或滥用零件,啥都不说了.我们欣慰地学习阅读.这两天残疾儿童是数学. 这是求所需的问题,不明确.贴上官方的解题报告. watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGluMzc1NjkxMDEx/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" align="middle" alt=""> 留着慢慢研…

有K个棋子在一个大小为N×N的棋盘.一开始,它们都在棋盘的顶端,它们起始的位置是 (1,a1),(1,a2),...,(1,ak) ,它们的目的地是 (n,b1),(n,b2),...,(n,bk). 一个位于 (r,c) 的棋子每一步只能向右走到 (r,c+1) 或者向下走到 (r+1,c) . 我们把 i 棋子从 (1,ai) 走到 (n,bi) 的路径记作 pi . 你的任务是计算有多少种方案把n个棋子送到目的地,并且对于任意两个不同的棋子 i,j ,使得路径 pi 与 pj 不相交(即没…

HDU 模拟题, 枚举1002 1004 1013 1015 1017 1020 1022 1029 1031 1033 1034 1035 1036 1037 1039 1042 1047 1048 1049 1050 1057 1062 1063 1064 1070 1073 1075 1082 1083 1084 1088 1106 1107 1113 1117 1119 1128 1129 1144 1148 1157 1161 1170 1172 1177 1197 1200 1201…

题意:考虑由$n$个结点构成的无向图,每条边的长度均为$1$,问有多少种构图方法使得结点$1$与任意其它节点之间的最短距离均不等于$k$(无法到达时距离等于无穷大),输出答案对$1e9+7$取模.$1 \leq n, k \leq 60$. 分析:只需要考虑那些和结点$1$在同一个连通块的结点,考虑对包含结点$1$的连通图的等价类划分:首先是结点数目,其次是所有结点到达结点$1$的最短距离的最大值,再次是最短距离等于该最大值的结点数目,因此用$dp(i, j, k)$表示与$1$在同一个连通分量…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4063 Description You are playing a flying game. In the game, player controls an aircraft in a 2D-space. The mission is to drive the craft from starting point to terminal point. The craft needs wireless s…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5444 Elven Postman Description Elves are very peculiar creatures. As we all know, they can live for a very long time and their magical prowess are not something to be taken lightly. Also, they live on tr…

A Walk Through the Forest Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 4383    Accepted Submission(s): 1573 Problem Description Jimmy experiences a lot of stress at work these days, especiall…

Counting Intersections 题目链接: http://acm.split.hdu.edu.cn/showproblem.php?pid=5862 Description Given some segments which are paralleled to the coordinate axis. You need to count the number of their intersection. The input data guarantee that no two se…

A Walk Through the Forest 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=1142 Description Jimmy experiences a lot of stress at work these days, especially since his accident made working difficult. To relax after a hard day, he likes to walk home. T…

http://acm.hdu.edu.cn/showproblem.php?pid=1151 Air Raid Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 7469   Accepted: 4451 Description Consider a town where all the streets are one-way and each street leads from one intersection to an…

L - House Building Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5538 Description Have you ever played the video game Minecraft? This game has been one of the world's most popular game in recent years. The wor…