poj 1696(极角排序)
Time Limit: 1000MS | Memory Limit: 10000K | |
Total Submissions: 3924 | Accepted: 2457 |
Description
- It can not turn right due to its special body structure.
- It leaves a red path while walking.
- It hates to pass over a previously red colored path, and never does that.
The pictures transmitted by the Discovery space ship depicts that
plants in the Y1999 grow in special points on the planet. Analysis of
several thousands of the pictures have resulted in discovering a magic
coordinate system governing the grow points of the plants. In this
coordinate system with x and y axes, no two plants share the same x or y.
An M11 needs to eat exactly one plant in each day to stay alive.
When it eats one plant, it remains there for the rest of the day with no
move. Next day, it looks for another plant to go there and eat it. If
it can not reach any other plant it dies by the end of the day. Notice
that it can reach a plant in any distance.
The problem is to find a path for an M11 to let it live longest.
Input is a set of (x, y) coordinates of plants. Suppose A with the
coordinates (xA, yA) is the plant with the least y-coordinate. M11
starts from point (0,yA) heading towards plant A. Notice that the
solution path should not cross itself and all of the turns should be
counter-clockwise. Also note that the solution may visit more than two
plants located on a same straight line.
Input
first line of the input is M, the number of test cases to be solved (1
<= M <= 10). For each test case, the first line is N, the number
of plants in that test case (1 <= N <= 50), followed by N lines
for each plant data. Each plant data consists of three integers: the
first number is the unique plant index (1..N), followed by two positive
integers x and y representing the coordinates of the plant. Plants are
sorted by the increasing order on their indices in the input file.
Suppose that the values of coordinates are at most 100.
Output
should have one separate line for the solution of each test case. A
solution is the number of plants on the solution path, followed by the
indices of visiting plants in the path in the order of their visits.
Sample Input
2
10
1 4 5
2 9 8
3 5 9
4 1 7
5 3 2
6 6 3
7 10 10
8 8 1
9 2 4
10 7 6
14
1 6 11
2 11 9
3 8 7
4 12 8
5 9 20
6 3 2
7 1 6
8 2 13
9 15 1
10 14 17
11 13 19
12 5 18
13 7 3
14 10 16
Sample Output
10 8 7 3 4 9 5 6 2 1 10
14 9 10 11 5 12 8 7 6 13 4 14 1 3 2
题意:一只蚂蚁走一个点集,每次只能往左走。。问最长能走的路。。
题解:我开始想到死胡同了,想用Graham解。。解不出来,,然后在网上找的解法。不停地排序排序。
http://www.cnblogs.com/ACMan/archive/2012/08/17/2644644.html大概就是这个过程。。
///判断线段与矩形是否相交
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
const double eps = 1e-;
const int N = ;
struct Point
{
int idx,x,y;
} p[N];
Point result[N];
int n,pos;
int cross(Point a,Point b,Point c)
{
return (a.x-c.x)*(b.y-c.y)-(a.y-c.y)*(b.x-c.x);
}
int dis(Point a,Point b)
{
return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
}
int cmp(Point a,Point b)
{
if(cross(a,b,p[pos])>) return ;
if(cross(a,b,p[pos])==&&dis(b,p[pos])>dis(a,p[pos])) return ;
return ;
} int main()
{
int tcase;
scanf("%d",&tcase);
while(tcase--)
{
scanf("%d",&n);
for(int i=; i<n; i++)
{
scanf("%d%d%d",&p[i].idx,&p[i].x,&p[i].y);
if( p[i].y < p[].y || (p[i].y == p[].y && p[i].x < p[].x) )
swap(p[],p[i]);
}
pos = ;
int j = ;
sort(p+,p+n,cmp);
result[j++] = p[pos++];
for (int i = ; i < n; i++)
{
sort(p + pos, p + n, cmp);
result[j++] = p[pos++];
}
result[j++] = p[pos++];
printf("%d", j);
for (int i = ; i < j; i++)
{
printf(" %d", result[i].idx);
}
printf("\n");
}
return ;
}
poj 1696(极角排序)的更多相关文章
- poj 1696 极角排序求最长逆时针螺旋线
Space Ant Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 4970 Accepted: 3100 Descrip ...
- poj 1696 极角排序(解题报告)
#include<iostream> #include<cmath> #include<algorithm> using namespace std; double ...
- Scrambled Polygon POJ - 2007 极角排序
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 // ...
- POJ - 2007 极角排序(Java 实现)
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 im ...
- Space Ant--poj1696(极角排序)
http://poj.org/problem?id=1696 极角排序是就是字面上的意思 按照极角排序 题目大意:平面上有n个点然后有一只蚂蚁他只能沿着点向左走 求最多能做多少点 分析: 其实 ...
- poj 1696 Space Ant (极角排序)
链接:http://poj.org/problem?id=1696 Space Ant Time Limit: 1000MS Memory Limit: 10000K Total Submissi ...
- POJ 1696 Space Ant 【极角排序】
题意:平面上有n个点,一只蚂蚁从最左下角的点出发,只能往逆时针方向走,走过的路线不能交叉,问最多能经过多少个点. 思路:每次都尽量往最外边走,每选取一个点后对剩余的点进行极角排序.(n个点必定能走完, ...
- POJ 1696 Space Ant(极角排序)
Space Ant Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 2489 Accepted: 1567 Descrip ...
- poj 1696:Space Ant(计算几何,凸包变种,极角排序)
Space Ant Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 2876 Accepted: 1839 Descrip ...
随机推荐
- 【翻译】ASP.NET Core 入门
ASP.NET Core 入门 原文地址:Introduction to ASP.NET Core 译文地址:asp.net core 简介 翻译:ganqiyin ...
- ArcGIS10.2中文版安装和破解教程
http://jingyan.baidu.com/article/e73e26c0cb5c1324adb6a791.html
- POI 导入 一直报400问题
排查过程:1.400一般都是参数或者请求不对,但是我这个情况是本地好用,只是服务器有问题,所以排除了传值的格式等问题. 2.服务器和本地网络隔离,所以没办法比较代码,分两次全量覆盖了html和js部分 ...
- 第四次JAVA作业
public class TvbDog { public static void main(String[] args) { Dog per=new Dog("陈狗"," ...
- 【bzoj5060】魔方国 乱搞+特判
题目描述 一张未知的有重边无自环的图,只知道点数为n,边数为m.可以标记若干个点,如果一个点被标记,那么与它距离不超过k的点(包括本身)都会被覆盖. 显然对于每张不同图,让所有点被覆盖的最小代价是不一 ...
- powershell入门教程-v0.3版
powershell入门教程-v0.3版 来源 https://www.itsvse.com/thread-3650-1-1.html 参考 http://www.cnblogs.com/piapia ...
- Problem Collection I 位运算
XOR ARC 092B CF 959E xor-MST CF 959F
- BZOJ4008. [HNOI2015]亚瑟王 期望概率dp
看到这道题想什么? 一个好转移的状态由于T最多444所以把每个点控制在O(400000)以内,所以对于n和r最多乘一次因此猜f[n][r],f[r][n],首先一轮一轮的搞不好转移,那么先想一想f[n ...
- BS架构下使用消息队列的工作流程
异步通信 对于BS(Browser-Server 浏览器)架构,很多情景下server的处理时间较长. 如果浏览器发送请求后,保持跟server的连接,等待server响应,那么一方面会对用户的体验有 ...
- linux下解压,压缩命令大全---方便新手查看
本文最后讲述如何在打包时排除某些文件 .tar 解包:tar xvf FileName.tar 打包:tar cvf FileName.tar DirName (注:tar是打包,不是压缩!) --- ...