USACO Section 4.3 Street Race(图的连通性+枚举)
虽说是IOI'95,但是也是挺水的..for 第一问,n最大为50,所以可以直接枚举起点和终点之外的所有点,然后dfs判断是否连通;for 第二问,易知答案一定是第一问的子集,所以从第一问中的答案中枚举,也是用dfs判断。
----------------------------------------------------------------------
----------------------------------------------------------------------
Street Race
IOI'95
Figure 1 gives an example of a course for a street race. You see some points, labeled from 0 to N (here, N=9), and some arrows connecting them. Point 0 is the start of the race; point N is the finish. The arrows represent one-way streets. The participants of the race move from point to point via the streets, in the direction of the arrows only. At each point, a participant may choose any outgoing arrow.
Figure 1: A street course with 10 points
A well-formed course has the following properties:
- Every point in the course can be reached from the start.
- The finish can be reached from each point in the course.
- The finish has no outgoing arrows.
A participant does not have to visit every point of the course to reach the finish. Some points, however, are unavoidable. In the example, these are points 0, 3, 6, and 9. Given a well-formed course, your program must determine the set of unavoidable points that all participants have to visit, excluding start and finish.
Suppose the race has to be held on two consecutive days. For that purpose the course has to be split into two courses, one for each day. On the first day, the start is at point 0 and the finish at some `splitting point'. On the second day, the start is at this splitting point and the finish is at point N. Given a well-formed course, your program must also determine the set of splitting points. A point S is a splitting point for the well-formed course C if S differs from the star t and the finish of C, and the course can be split into two well-formed courses that (1) have no common arrows and (2) have S as their only common point, with S appearing as the finish of one and the start of the other. In the example, only point 3 is a splitting point.
PROGRAM NAME: race3
INPUT FORMAT
The input file contains a well-formed course with at most 50 points and at most 100 arrows. There are N+2 lines in the file. The first N+1 lines contain the endpoints of the arrows that leave from the points 0 through N respectively. Each of these lines ends with the number -2. The last line contains only the number -1.
SAMPLE INPUT (file race3.in)
1 2 -2
3 -2
3 -2
5 4 -2
6 4 -2
6 -2
7 8 -2
9 -2
5 9 -2
-2
-1
OUTPUT FORMAT
Your program should write two lines. The first line should contain the number of unavoidable points in the input course, followed by the labels of these points, in ascending order. The second line should contain the number of splitting points of the input course, followed by the labels of all these points, in ascending order.
SAMPLE OUTPUT (file race3.out)
2 3 6
1 3
USACO Section 4.3 Street Race(图的连通性+枚举)的更多相关文章
- USACO 4.3 Street Race
Street RaceIOI'95 Figure 1 gives an example of a course for a street race. You see some points, labe ...
- USACO Section 4
前言 好久没更新这个系列了,最近闲的无聊写一下.有两题搜索懒得写了. P2737 [USACO4.1]麦香牛块Beef McNuggets https://www.luogu.com.cn/probl ...
- 数据结构-图-Java实现:有向图 图存储(邻接矩阵),最小生成树,广度深度遍历,图的连通性,最短路径1
import java.util.ArrayList; import java.util.List; // 模块E public class AdjMatrixGraph<E> { pro ...
- Victoria的舞会2——图的连通性及连通分量
[Vijos1022]]Victoria的舞会2 Description Victoria是一位颇有成就的艺术家,他因油画作品<我爱北京天安门>闻名于世界.现在,他为了报答帮助他的同行们, ...
- POJ 2513 - Colored Sticks - [欧拉路][图的连通性][字典树]
题目链接: http://poj.org/problem?id=2513 http://bailian.openjudge.cn/practice/2513?lang=en_US Time Limit ...
- poj 3310(并查集判环,图的连通性,树上最长直径路径标记)
题目链接:http://poj.org/problem?id=3310 思路:首先是判断图的连通性,以及是否有环存在,这里我们可以用并查集判断,然后就是找2次dfs找树上最长直径了,并且对树上最长直径 ...
- POJ2513(字典树+图的连通性判断)
//用map映射TLE,字典树就AC了#include"cstdio" #include"set" using namespace std; ; ;//26个小 ...
- 图的连通性问题的小结 (双连通、2-SAT)
图的连通性问题包括: 1.强连通分量. 2.最小点基和最小权点基. 3.双连通. 4.全局最小割. 5.2-SAT 一.强连通分量 强连通分量很少单独出题,一般都是把求强连通分量作为缩点工具. 有三种 ...
- 2018年牛客多校寒假 第四场 F (call to your teacher) (图的连通性)
题目链接 传送门:https://ac.nowcoder.com/acm/contest/76/F 思路: 题目的意思就是判断图的连通性可以用可达性矩阵来求,至于图的存储可以用邻接矩阵来储存,求出来可 ...
随机推荐
- C# DataTable转实体 通用方法【转】
public static T GetEntity<T>(DataTable table) where T : new() { T entity = new T(); ...
- Afinal开源框架中FinalActivity的使用
1. 首先将afinal.jar文件复制到项目中的libs文件夹下 2. 让MainActivity不在继承系统的Activity,而是继承FinalActivity public class Mai ...
- 1005 Number Sequence(HDU)
题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1005 Number Sequence Time Limit: 2000/1000 MS (Java/O ...
- DOM 样式操作
通过js动态的修改样式 更新样式的方法:一.使用.style方法修改样式,缺点是使样式混杂在js中,再次修改不易.二.更新class属性,更改样式.三.一次性更改很多元素样式(如换肤操作),更改样式表 ...
- Spring-----Spring整合Struts2实例
转载自:http://blog.csdn.net/hekewangzi/article/details/51713058
- U3D学习使用笔记(二)
1.在移动端www.texture使用时不能实时加载纹理,www.LoadImageIntoTexture使用没问题 2.public FaceFeature FaceFeatureData ...
- c语言中的#ifndef、#def、#endif等宏是什么意思
#ifndef.(或者#ifndef).#def.#endif等宏这几个宏是为了进行条件编译.一般情况下,源程序中所有的行都参加编译.但是有时希望对其中一部分内容只在满足一定条件才进行编译,也就是对一 ...
- Bower —— 一个Web的包管理工具
作者:江剑锋 github地址:https://github.com/bower/bower Bower为何物 Bower是一个Web开发的包管理软件.前端开发中,或多或少,都会以来于现成的fra ...
- MRP工作台任务下达之计划组为必输
应用 Oracle Manufacturing Planning 层 Level Function 函数名 Funcgtion Name MRPFPPWB 表单名 Form Name MRPS ...
- Java学习之InputStream中read()与read(byte[] b)
Java学习之InputStream中read()与read(byte[] b) 这两个方法在抽象类InputStream中都是作为抽象方法存在的, JDK API中是这样描述两者的: read() ...