Mall 水题:注意题目上面有一个至少离城堡的距离为L,其实思考一下就知道是指离凸包(凸多边形)的距离为L,这时很容易知道外围的圆的圆心角叠加之后就是一个整圆:和poj2187一样使用graham形成凸包:还有就是开始我四舍五入用floor(),却使用%d输出,导致一直输出是0:因为floor()的返回值也是浮点型... #include<iostream> #include<cstdio> #include<cstring> #include<string.h&…

Wall Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 28157   Accepted: 9401 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he wo…

Wall Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 33888   Accepted: 11544 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he w…

LINK 题意:给出一个简单几何,问与其边距离长为L的几何图形的周长. 思路:求一个几何图形的最小外接几何,就是求凸包,距离为L相当于再多增加上一个圆的周长(因为只有四个角).看了黑书使用graham算法极角序求凸包会有点小问题,最好用水平序比较好.或者用Melkman算法 /** @Date : 2017-07-13 14:17:05 * @FileName: POJ 1113 极角序求凸包 基础凸包.cpp * @Platform: Windows * @Author : Lweleth (…

题目链接:poj 1113   单调链凸包小结 题解:本题用到的依然是凸包来求,最短的周长,只是多加了一个圆的长度而已,套用模板,就能搞定: AC代码: #include<iostream> #include<algorithm> #include<cstdio> #include<cmath> using namespace std; int m,n; struct p { double x,y; friend int operator <(p a,…

http://poj.org/problem?id=1113 夏令营讲课时的求凸包例题,据说是PKUSC2015的一道题 我WA两次错在四舍五入上了(=ﾟωﾟ)ﾉ #include<cmath> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; double Pi = acos(-1); const int N = 1003; struct Point {…

题目链接:http://poj.org/problem?id=1113 题目大意:给出点集和一个长度L,要求用最短长度的围墙把所有点集围住,并且围墙每一处距离所有点的距离最少为L,求围墙的长度. 解法:凸包+以L为半径的圆的周长.以题目中的图为例,两点之间的围墙长度之和正好就是凸包的长度,再加上每个点的拐角处(注意此处为弧,才能保证城墙距离点的距离最短)的长度. #include<iostream> #include<cstdio> #include<cstdlib>…

题链: http://poj.org/problem?id=1113 题解: 计算几何,凸包 题意:修一圈围墙把给出的点包围起来,且被包围的点距离围墙的距离不能小于L,求围墙最短为多少. 答案其实就是等于N个点的凸包的周长+半径为L的圆的周长. 代码: #include<cmath> #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #define…

[题目链接] http://poj.org/problem?id=1113 [题目大意] 给出一个城堡,要求求出距城堡距离大于L的地方建围墙将城堡围起来求所要围墙的长度 [题解] 画图易得答案为凸包的周长加一个圆的周长. [代码] #include <cstdio> #include <algorithm> #include <cmath> #include <vector> using namespace std; double EPS=1e-10; co…

题目: http://poj.org/problem?id=1113 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=22013#problem/F Wall Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 26219   Accepted: 8738 Description Once upon a time there was a greedy King who…