The Designer Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1115    Accepted Submission(s): 217 Problem Description Nowadays, little haha got a problem from his teacher.His teacher wants to des…

传送门:http://acm.hdu.edu.cn/showproblem.php?pid=6158 本题是一个计算几何题——四圆相切. 平面上的一对内切圆,半径分别为R和r.现在这一对内切圆之间,按照如图所示的方式依次放置N个相切的圆.求放置的这N个圆的面积之和. 在此,首先介绍一个定理:笛卡尔定理.Wiki: Descartes' theorem. 平面上的四个圆,第i个圆的半径为r[i],曲率为κ[i](注:κ=r­-1).若这四个圆中的每一对均构成外切,则其曲率满足约束: $\left(…

The Designer Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 761    Accepted Submission(s): 142 Problem Description Nowadays, little haha got a problem from his teacher.His teacher wants to desi…

LINK 题意:一个大圆中内切两个圆,三个圆两两相切,再不断往上加新的相切圆,问加上的圆的面积和.具体切法看图 思路:笛卡尔定理: 若平面上四个半径为r1.r2.r3.r4的圆两两相切于不同点,则其半径满足以下结论: (1)若四圆两两外切,则    (2)若半径为r1.r2.r3的圆内切于半径为r4的圆中,则    显然现在是第二种情况,设弧度为$k$则,$r_1,r_2,r_3,r_4$的弧度为$k_1,k_2,k_3,k_4$,其中$r_4$是下个我们要求的圆的半径,显然我们已知前三个圆,第…

题目链接多校8-1009 HDU - 6158 The Designer 题意 T(<=1200)组,如图在半径R1.R2相内切的圆的差集位置依次绘制1,2,3,到n号圆,求面积之和(n<=1e7). 题解 圆的反演: (圆的反演就是半径为R,圆心O的圆为反演中心,点P的反演点就是在射线OP上满足\(|OP'|*|OP|=R^2\)的点P') 设切点为O,以O为圆心半径R的圆为反演点.将圆R1和R2反演得到两条直线,和两条直线相切的圆反演回去的圆就是1-n号圆的圆心. 那么它们的直径就是这些小…

地址:http://acm.split.hdu.edu.cn/showproblem.php?pid=6158 题目: The Designer Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1381    Accepted Submission(s): 289 Problem Description Nowadays, little …

深度搜索 剪枝 还不是很理解 贴上众神代码 //http://blog.csdn.net/vsooda/article/details/7884772#include<iostream> #include<math.h> using namespace std; char map[10][10]; int N,M,T; int di,dj,escape; int dir[4][2]={{0,-1},{0,1},{1,0},{-1,0}}; void dfs(int x,int y,…

http://acm.hdu.edu.cn/showproblem.php?pid=1284 New~ 欢迎“热爱编程”的高考少年——报考杭州电子科技大学计算机学院关于2015年杭电ACM暑期集训队的选拔 钱币兑换问题 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 7265    Accepted Submission(s): 4268…

http://acm.hdu.edu.cn/showproblem.php?pid=1548 Online Judge Online Exercise Online Teaching Online Contests Exercise Author F.A.QHand In HandOnline Acmers Forum |DiscussStatistical Charts Problem ArchiveRealtime Judge StatusAuthors Ranklist       C/C…

Balanced Sequence Time Limit: / MS (Java/Others) Memory Limit: / K (Java/Others) Total Submission(s): Accepted Submission(s): Problem Description Chiaki has n strings s1,s2,…,sn consisting of '(' and ')'. A string of this type is said to be balanced:…