hdu4081(秦始皇的道路系统)
Qin Shi Huang undertook gigantic projects, including the first version of the Great Wall of China, the now famous city-sized mausoleum guarded by a life-sized Terracotta Army, and a massive national road system. There is a story about the road system:
There were n cities in China and Qin Shi Huang wanted them all be connected by n-1 roads, in order that he could go to every city from the capital city Xianyang.
Although Qin Shi Huang was a tyrant, he wanted the total length of all roads to be minimum,so that the road system may not cost too many people's life. A daoshi (some kind of monk) named Xu Fu told Qin Shi Huang that he could build a road by magic and that magic road would cost no money and no labor. But Xu Fu could only build ONE magic road for Qin Shi Huang. So Qin Shi Huang had to decide where to build the magic road. Qin Shi Huang wanted the total length of all none magic roads to be as small as possible, but Xu Fu wanted the magic road to benefit as many people as possible ---- So Qin Shi Huang decided that the value of A/B (the ratio of A to B) must be the maximum, which A is the total population of the two cites connected by the magic road, and B is the total length of none magic roads.
Would you help Qin Shi Huang?
A city can be considered as a point, and a road can be considered as a line segment connecting two points.
InputThe first line contains an integer t meaning that there are t test cases(t <= 10).
For each test case:
The first line is an integer n meaning that there are n cities(2 < n <= 1000).
Then n lines follow. Each line contains three integers X, Y and P ( 0 <= X, Y <= 1000, 0 < P < 100000). (X, Y) is the coordinate of a city and P is the population of that city.
It is guaranteed that each city has a distinct location.OutputFor each test case, print a line indicating the above mentioned maximum ratio A/B. The result should be rounded to 2 digits after decimal point.Sample Input
2
4
1 1 20
1 2 30
200 2 80
200 1 100
3
1 1 20
1 2 30
2 2 40
Sample Output
65.00
70.00
图片不错,题目copy一遍
题解:这道题手打了一个半小时,体会甚多,暑假就想打了,wsj讲了一次,但是那是不理解,然后又听力茹老师讲课,理解了一些,
最后zyh又讲了一次,自己理会,都懂了,一开始打了kruskal算法,但是T了,额,然后用了prim强行优化了一个log速度就快了不
少,都怪那个T组数据。题目的话就是先Prim求出最小生成树,然后bfs求出个点对之间简单路径的最大边,然后枚举点对,O(1)解
决,就差不多了复杂度O(Tn^2)
hdu4081(秦始皇的道路系统)的更多相关文章
- hdu4081 秦始皇修路(次小生成树)
题目ID:hdu4081 秦始皇修路 题目链接:点击打开链接 题目大意:给你若干个坐标,每个坐标表示一个城市,每个城市有若干个人,现在要修路,即建一个生成树,然后有一个魔法师可以免费造路(不消耗人 ...
- 最小生成树的变形(次小生成树hdu4081)
hdu4081 Qin Shi Huang's National Road System Time Limit: 2000/1000 MS (Java/Others) Memory Limit: ...
- LA 5713 秦始皇修路 MST
题目链接:http://vjudge.net/contest/144221#problem/A 题意: 秦朝有n个城市,需要修建一些道路使得任意两个城市之间都可以连通.道士徐福声称他可以用法术修路,不 ...
- UVALive 5713 Qin Shi Huang's National Road System秦始皇修路(MST,最小瓶颈路)
题意: 秦始皇要在n个城市之间修路,而徐福声可以用法术位秦始皇免费修1条路,每个城市还有人口数,现要求徐福声所修之路的两城市的人口数之和A尽量大,而使n个城市互通需要修的路长B尽量短,从而使得A/B最 ...
- hdu4081 次小生成树变形
pid=4081">http://acm.hdu.edu.cn/showproblem.php?pid=4081 Problem Description During the Warr ...
- hdu4081
hdu4081 题意 给出n个点坐标,每个点有权值,要求得到一颗生成树,且其中有一条道路修建不需要花费,但是要求这条道路所连接的两点的权值之和除以剩下所有道路的距离花费最大. 分析 首先求最小生成树, ...
- HDU4081 Qin Shi Huang's National Road System 2017-05-10 23:16 41人阅读 评论(0) 收藏
Qin Shi Huang's National Road System ...
- LA5713 秦始皇修路 (mst)
题意: 秦朝有n个城市,需要修路让每个城市都互相连通,现在可以免费修一条路,秦始皇希望他除了这条免费修的路外所需修的路的总和B最短,同时这条免费的路连接的人口之和A尽可能大,求最大的A/B是多少,城市 ...
- LA 5713 秦始皇修路
https://vjudge.net/problem/UVALive-5713 题意: 秦朝有n个城市,需要修建一些道路使得任意两个城市之间都可以连通.道士徐福声称他可以用法术修路,不花钱,也不用劳动 ...
随机推荐
- 优化关键渲染路径CRP
什么是关键渲染路径? 从收到 HTML.CSS 和 JavaScript 字节到对其进行必需的处理,从而将它们转变成渲染的像素这一过程中有一些中间步骤 浏览器渲染页面前需要先构建 DOM 和 CSSO ...
- SpringMVC入门第二天
SpringMVC第二天 1. 回顾 1.Springmvc介绍? Springmvc是Spring公司 2.Springmvc入门程序 第一步:Web工程 第二步:导Jar包 第三步:web.x ...
- Spring Cloud官方文档中文版-服务发现:Eureka服务端
官方文档地址为:http://cloud.spring.io/spring-cloud-static/Dalston.SR3/#spring-cloud-eureka-server 文中例子我做了一些 ...
- 堆排序Java实现
package practice; import edu.princeton.cs.algs4.StdRandom; public class TestMain { public static voi ...
- redis info 命令详解
详见:http://blog.yemou.net/article/query/info/tytfjhfascvhzxcyt119 Redis Info 命令以一种易于理解和阅读的格式,返回关于 Red ...
- windows系统,优化C盘空间的方法
C盘在使用过程中,内容会越来越多,剩余空间越来越小.如何清理出更多空间呢?以windows7为例 转载请保留 http://www.cnblogs.com/lion-zheng/ cleanmgr w ...
- nginx小问题
配置nginx与ftp图片服务器:安装后,要在/usr/local/nginx/conf/nginx.conf里面的server中(带有localhost的那一块)修改为location \ {roo ...
- 福州大学软工 1715 | K 班 - 启航
福州大学软工 1715 | K 班 - 启航 愉快的暑假已经接近尾声了,我猜很多同学的暑假都过得轻松,毕竟是夏天(空调/WiFi/西瓜).不过呢,暑假期间的老师.助教们可没有闲着,都在为接下来的软工实 ...
- 第二次项目冲刺(Beta阶段)第一天
a. 安排连续七天的敏捷冲刺. 2017.5.18完成冲刺计划安排 2017.5.20完善主页面 1st day(目前位置) 2017.5.21完善功能 2st day 2017.5.22添加自定义重 ...
- 201521123100 《Java程序设计》 第7周学习总结
1. 本周学习总结 以你喜欢的方式(思维导图或其他)归纳总结集合相关内容. 参考资料: XMind 2. 书面作业 1.ArrayList代码分析 1.1 解释ArrayList的contains源代 ...