题意:逆时针给出N个点,求这个多边形是否有核. 思路:半平面交求多边形是否有核.模板题. 定义: 多边形核:多边形的核可以只是一个点,一条直线,但大多数情况下是一个区域(如果是一个区域则必为 ).核内的点与多边形所有顶点的连线均在多边形内部. 半平面交:对于平面,任何直线都能将平面划分成两部分,即两个半平面.半平面交既是多个半平面的交集.定义如其名. 半平面交求多边形的核. 设多边形点集为 *p,核的点集为*cp. 开始时将p的所有点放到cp内,然后枚举多边形的所有边去切割cp,cp中在边内侧的…

/* poj 3130 How I Mathematician Wonder What You Are! - 求多边形有没有核 */ #include <stdio.h> #include<math.h> const double eps=1e-8; const int N=103; struct point { double x,y; }dian[N]; inline bool mo_ee(double x,double y) { double ret=x-y; if(ret&l…

求半平面交的算法是zzy大神的排序增量法. ///Poj 1474 #include <cmath> #include <algorithm> #include <cstdio> using namespace std; ; //点 class Point { public: double x, y; Point(){} Point(double x, double y):x(x),y(y){} bool operator < (const Point &…

题目链接:POJ 3130 Problem Description After counting so many stars in the sky in his childhood, Isaac, now an astronomer and a mathematician uses a big astronomical telescope and lets his image processing program count stars. The hardest part of the prog…

http://poj.org/problem?id=3130 #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #define maxn 1000000 using namespace std; ); struct point { double x,y; }; double a,b,c; ,m; point p1[maxn]; point p2[maxn];…

/*************** poj 3335 点序顺时针 ***************/ #include <iostream> #include <cmath> #include <algorithm> using namespace std; ; const double maxn = 0x7f7f7f7f; int dcmp(double x){ if(fabs(x)<eps) ; else ?-:; } struct point { double…

题目链接 题意 : 给你一个多边形,问你该多边形中是否存在一个点使得该点与该多边形任意一点的连线都在多边形之内. 思路 : 与3335一样,不过要注意方向变化一下. #include <stdio.h> #include <string.h> #include <iostream> #include <math.h> using namespace std ; struct node { double x; double y ; } p[],temp[],n…

题目大意:判断多多边形是否存在内核. 代码如下: #include<iostream> #include<string.h> #include<stdio.h> #include<algorithm> #include<math.h> #include<queue> using namespace std; ; ; ; int Sign(double t) { if(t > EPS) ; if(fabs(t) < EPS)…

题意:求问多边形的核(能够看到所有点的点)是否存在. /* 对于这样的题目,我只能面向std编程了,然而还是不理解. 算法可参考:http://www.cnblogs.com/huangxf/p/4067763.html */ #include<cstdio> #include<iostream> #include<cmath> #define N 110 using namespace std; int m; double r; int cCnt,curCnt;///…

求多边形的核,直接把所有边求半平面交判断有无即可 #include<iostream> #include<cstdio> #include<algorithm> #include<cmath> using namespace std; const int N=205; const double eps=1e-6; int n; struct dian { double x,y; dian(double X=0,double Y=0) { x=X,y=Y; }…

这题,加了精度错了,不加精度反而对了... #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> using namespace std; const int MAXN=110; const double eps=1e-8; struct point { double x,y; }; point pts[MAXN…

Description After counting so many stars in the sky in his childhood, Isaac, now an astronomer and a mathematician uses a big astronomical telescope and lets his image processing program count stars. The hardest part of the program is to judge if shi…

转自:http://blog.csdn.net/tyger/article/details/4480029 计算几何题的特点与做题要领:1.大部分不会很难,少部分题目思路很巧妙2.做计算几何题目,模板很重要,模板必须高度可靠.3.要注意代码的组织,因为计算几何的题目很容易上两百行代码,里面大部分是模板.如果代码一片混乱,那么会严重影响做题正确率.4.注意精度控制.5.能用整数的地方尽量用整数,要想到扩大数据的方法(扩大一倍,或扩大sqrt2).因为整数不用考虑浮点误差,而且运算比浮点快. 一.点…

OJ上的一些水题(可用来练手和增加自信) (POJ 3299,POJ 2159,POJ 2739,POJ 1083,POJ 2262,POJ 1503,POJ 3006,POJ 2255,POJ 3094) 初期: 一.基本算法: 枚举. (POJ 1753,POJ 2965) 贪心(POJ 1328,POJ 2109,POJ 2586) 递归和分治法. 递推. 构造法.(POJ 3295) 模拟法.(POJ 1068,POJ 2632,POJ 1573,POJ 2993,POJ 2996) 二…

著名题单,最初来源不详.直接来源:http://blog.csdn.net/a1dark/article/details/11714009 OJ上的一些水题(可用来练手和增加自信) (POJ 3299,POJ 2159,POJ 2739,POJ 1083,POJ 2262,POJ 1503,POJ 3006,POJ 2255,POJ 3094) 初期: 一.基本算法: 枚举. (POJ 1753,POJ 2965) 贪心(POJ 1328,POJ 2109,POJ 2586) 递归和分治法. 递…

//第一期 计算几何题的特点与做题要领: 1.大部分不会很难,少部分题目思路很巧妙 2.做计算几何题目,模板很重要,模板必须高度可靠. 3.要注意代码的组织,因为计算几何的题目很容易上两百行代码,里面大部分是模板.如果代码一片混乱,那么会严重影响做题正确率. 4.注意精度控制. 5.能用整数的地方尽量用整数,要想到扩大数据的方法(扩大一倍,或扩大sqrt2).因为整数不用考虑浮点误差,而且运算比浮点快. 一.点,线,面,形基本关系,点积叉积的理解 POJ 2318 TOYS(推荐) http:/…

博客原文地址:http://blog.csdn.net/xuechelingxiao/article/details/40859973 这两天刷了POJ上几道半平面交,对半平面交有了初步的体会,感觉半平面交还是个挺有用的知识点. 半平面交主要是看的ZZY的国家队论文,他提出的是一种O(n×log(n))的排序增量法. 附论文地址: 算法合集之<半平面交的新算法及其有用价值>. POJ 3335 Rotating Scoreboard 题目大意: World finals 要開始了,比赛场地是一…

KUANGBIN带你飞 全专题整理 https://www.cnblogs.com/slzk/articles/7402292.html 专题一 简单搜索 POJ 1321 棋盘问题    //2019.3.18 POJ 2251 Dungeon Master POJ 3278 Catch That Cow  //4.8 POJ 3279 Fliptile POJ 1426 Find The Multiple  //4.8 POJ 3126 Prime Path POJ 3087 Shuffle…

[kuangbin带你飞]专题1-23 专题一 简单搜索 POJ 1321 棋盘问题POJ 2251 Dungeon MasterPOJ 3278 Catch That CowPOJ 3279 FliptilePOJ 1426 Find The MultiplePOJ 3126 Prime PathPOJ 3087 Shuffle'm UpPOJ 3414 PotsFZU 2150 Fire GameUVA 11624 Fire!POJ 3984 迷宫问题HDU 1241 Oil Deposit…

专题一 简单搜索 POJ 1321 棋盘问题POJ 2251 Dungeon MasterPOJ 3278 Catch That CowPOJ 3279 FliptilePOJ 1426 Find The MultiplePOJ 3126 Prime PathPOJ 3087 Shuffle'm UpPOJ 3414 PotsFZU 2150 Fire GameUVA 11624 Fire!POJ 3984 迷宫问题HDU 1241 Oil DepositsHDU 1495 非常可乐HDU 26…

Halloween treats Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 7644   Accepted: 2798   Special Judge Description Every year there is the same problem at Halloween: Each neighbour is only willing to give a certain total number of sweets…

Find a multiple Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7192   Accepted: 3138   Special Judge Description The input contains N natural (i.e. positive integer) numbers ( N <= 10000 ). Each of that numbers is not greater than 15000…

The Pilots Brothers' refrigerator Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 22286   Accepted: 8603   Special Judge Description The game “The Pilots Brothers: following the stripy elephant” has a quest where a player needs to open a…

Flip Game Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 37427   Accepted: 16288 Description Flip game is played on a rectangular 4x4 field with two-sided pieces placed on each of its 16 squares. One side of each piece is white and the…

Corn Fields Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 9806   Accepted: 5185 Description Farmer John has purchased a lush new rectangular pasture composed of M by N (1 ≤ M ≤ 12; 1 ≤ N ≤ 12) square parcels. He wants to grow some yumm…

Sum of Consecutive Prime Numbers Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 20050   Accepted: 10989 Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representatio…

Tree Recovery Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11939   Accepted: 7493 Description Little Valentine liked playing with binary trees very much. Her favorite game was constructing randomly looking binary trees with capital le…

Seek the Name, Seek the Fame Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 17898   Accepted: 9197 Description The little cat is so famous, that many couples tramp over hill and dale to Byteland, and asked the little cat to give names t…

题目: poj 2352 Stars 数星星 题意:已知n个星星的坐标.每个星星都有一个等级,数值等于坐标系内纵坐标和横坐标皆不大于它的星星的个数.星星的坐标按照纵坐标从小到大的顺序给出,纵坐标相同时则按照横坐标从小到大输出. (0 <= x, y <= 32000) 要求输出等级0到n-1之间各等级的星星个数. 分析: 这道题不难想到n平方的算法,即从纵坐标最小的开始搜,每次找它前面横坐标的值比它小的点的个数,两个for循环搞定,但是会超时. 所以需要用一些数据结构去优化,主要是优化找 横坐…

poj   1251  Jungle Roads  (最小生成树) Link: http://poj.org/problem?id=1251 Jungle Roads Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 23507   Accepted: 11012 Description The Head Elder of the tropical island of Lagrishan has a problem. A b…