题意: 给你n个点,这n个点可以构成一个多边形(但是不是按顺序给你的).原点(0,0)为起点,让你按顺序逆序输出所有点 题解: 就是凸包问题的极角排序 用double一直Wa,改了int就可以了 //原点(0,0)为起点,逆序输出多边形的点 #include<stdio.h> #include<string.h> #include<iostream> #include<algorithm> #include<queue> #include<…

题目链接 题意 : 对输入的点极角排序 思路 : 极角排序方法 #include <iostream> #include <cmath> #include <stdio.h> #include <algorithm> using namespace std; struct point { double x,y; }p[],pp; double cross(point a,point b,point c) { return (a.x-c.x)*(b.y-c.y…

水题,根本不用凸包,就是一简单的极角排序. 叉乘<0,逆时针. #include <iostream> #include <cstdio> #include <cstring> #include <string> #include <algorithm> using namespace std; const int maxn=55; struct point { double x,y; } p[maxn]; double cross(poi…

POJ 2007 将所有的点按逆时针输出 import java.io.*; import java.util.*; public class Main { static class Point implements Comparable<Point>{ double x, y; @Override public int compareTo(Point a) { return (int)cross(a); } public double cross(Point a){ return a.x*y…

给一些点,这些点都是一个凸包上的顶点,以第一个点为起点顺时针把别的点拍排一下序列. 分析:最简单的极坐标排序了..................... 代码如下: -------------------------------------------------------------------------------------------------------------------------- #include<iostream> #include<algorithm>…

Space Ant Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 4970   Accepted: 3100 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…

#include<iostream> #include<cmath> #include<algorithm> using namespace std; double eps=1e-8; int sgn(double x) { if(fabs(x)<=eps)return 0; if(x<0)return -1; return 1; } struct Point { double x,y; int index; Point (){} Point(double…

Space Ant Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 3924   Accepted: 2457 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…

Scrambled Polygon Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 8636   Accepted: 4105 Description A closed polygon is a figure bounded by a finite number of line segments. The intersections of the bounding line segments are called the…

题目传送门 题意:裸的对原点的极角排序,凸包貌似不行. /************************************************ * Author :Running_Time * Created Time :2015/11/3 星期二 14:46:47 * File Name :POJ_2007.cpp ************************************************/ #include <cstdio> #include <al…