题目大意: 不能向左拐 不能重复走 就是求一个螺旋凸包 把已经是凸包内的点标记一下就行 因为凸包的性质 所有点都能走到 注意起点的选择 还有 反复求凸包的过程中边界的改变 #include <cstdio> #include <algorithm> #include <string.h> #include <cmath> using namespace std; ; ; double add(double a,double b) { ; return a+b…

题目大意:给一些散列点然后初始点是坐标最下面最左面的点,然后只能往左走,求出来最多可以经过多少个点,把序号输出出来.   分析:先求出来初始的点,然后不断排序找出来最近的凸点....复杂度是 n^2*log(n)....不多点很少,所以随意玩.   代码如下: ===================================================================================================================== #…

Technorati Tags: POJ,计算几何,凸包 初学计算几何,引入polygon后的第一个挑战--凸包 此题可用凸包算法做,只要把压入凸包的点从原集合中排除即可,最终形成图形为螺旋线. 关于凸包,具体可见凸包五法:http://blog.csdn.net/bone_ace/article/details/46239187 此处简述我O(nH)的Jarvis法(H: 凸包上点数) 过程较易于理解. //POJ1696 //凸包变形 //AC 2016.10.13 #include "cs…

The Fortified Forest Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 6198   Accepted: 1744 Description Once upon a time, in a faraway land, there lived a king. This king owned a small collection of rare and valuable trees, which had been…

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…

Space Ant Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 3967   Accepted: 2489 Description The most exciting space discovery occurred at the end of the 20th century. In 1999, scientists traced down an ant-like creature in the planet Y19…

poj 1696 Space Ant 链接:http://poj.org/problem?id=1696 题意:在坐标轴上,给定n个点的 id 以及点的坐标(xi, yi),让你以最底端点开始,从右依次找出最外围的的点,形成一个螺旋状的图像.图形见题目例题,输出他们的 id. 思路:先找出最下面的点,然后依次为“据点”,对其他点进行极角排序,取出第一个点,以此点为“据点”,对其他未选择的点极角排序,选出排序后第一个点,……, 依此类推,取得 n 个点.复杂度(n^2*log(n)). 代码: #…

Poj 2187 凸包模板求解 传送门 由于整个点数是50000,而求凸包后的点也不会很多,因此直接套凸包之后两重循环即可求解 #include <queue> #include <cmath> #include <cstdio> #include <cstring> #include <cstdlib> #include <iostream> #include <algorithm> #define ll long lo…

题目传送门 题意:一个蚂蚁一直往左边走,问最多能走多少步,且输出路径 分析:就是凸包的变形题,凸包性质,所有点都能走.从左下角开始走,不停排序.有点纠结,自己的凸包不能AC.待理解透凸包再来写.. 好像只能用卷包裹法来写,就是从一个起点出发,每次相对于起点用叉积排序,选择最外侧的点,更新起点. /************************************************ * Author :Running_Time * Created Time :2015/10/27 星期…

Space Ant Time Limit: 1000MS Memory Limit: 10000K Description The most exciting space discovery occurred at the end of the 20th century. In 1999, scientists traced down an ant-like creature in the planet Y1999 and called it M11. It has only one eye o…