一个n个点的凸多边形,求多边形中离多边形边界最远的距离.实际上就是求凸包最大内接圆的半径. 利用半平面交求解,每次二分枚举半径d,然后将凸包每条边所代表的半平面沿其垂直单位法向量平移d,看所有平移后的半平面的交集是否为空. #include<algorithm> #include<iostream> #include<cstring> #include<cstdlib> #include<fstream> #include<sstream&…

题意:求一个凸多边形中一点到边的最大距离. 思路:转换成在多边形内部,到每边距离为d的直线所围成的内多边形是否存在.也就是,二分距离+半平面交. #include<cstdio> #include<cmath> #include<cstring> #include<algorithm> #include<iostream> #include<memory.h> #include<cstdlib> #include<v…

Most Distant Point from the Sea [题目链接]Most Distant Point from the Sea [题目类型]半平面交 &题解: 蓝书279 二分答案,判断平移后的直线的半平面交是否为空. 模板是照着敲的,还有一些地方不是很懂, 应该还要慢慢体会吧 &代码: #include <cstdio> #include <cmath> #include <algorithm> #include <vector>…

题目传送门 题意:凸多边形的小岛在海里,问岛上的点到海最远的距离. 分析:训练指南P279,二分答案,然后整个多边形往内部收缩,如果半平面交非空,那么这些点构成半平面,存在满足的点. /************************************************ * Author :Running_Time * Created Time :2015/11/10 星期二 14:16:17 * File Name :LA_3890.cpp ********************…

题目链接:http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=11358 [思路] 二分法+半平面交 二分与海边的的距离,由法向量可以得到平移后的各边,半平面交在特定精度判断是否有交集. [代码] #include<cmath> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; ; stru…

Most Distant Point from the Sea Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 5153   Accepted: 2326   Special Judge Description The main land of Japan called Honshu is an island surrounded by the sea. In such an island, it is natural t…

二分+计算几何/半平面交 半平面交的学习戳这里:http://blog.csdn.net/accry/article/details/6070621 然而这题是要二分长度r……用每条直线的距离为r的平行线来截“凸包” 做平行线的方法是:对于向量(x,y),与它垂直的向量有:(y,-x)和(-y,x),然后再转化成单位向量,再乘以 r ,就得到了转移向量tmp,设直线上两点为A(x1,y1),B(x2,y2),用这个方法就找到了直线AB的平行线CD,其中C=A+tmp,D=b+tmp; 然而我傻逼…

Most Distant Point from the Sea Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 3476   Accepted: 1596   Special Judge Description The main land of Japan called Honshu is an island surrounded by the sea. In such an island, it is natural t…

Description The main land of Japan called Honshu is an island surrounded by the sea. In such an island, it is natural to ask a question: “Where is the most distant point from the sea?” The answer to this question for Honshu was found in 1996. The mos…

Most Distant Point from the Sea Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 3955   Accepted: 1847   Special Judge Description The main land of Japan called Honshu is an island surrounded by the sea. In such an island, it is natural t…