博客
关于我
Command Network POJ - 3164(最小树形图/朱刘算法)
阅读量:275 次
发布时间:2019-03-01

本文共 4010 字,大约阅读时间需要 13 分钟。

题意:

1到所有点的最短距离,有向,最短,最小树形图(朱刘算法),板子题。没有任何坑点。

不会的点。
学吧!
挺简单的。

注意:

别交G++,用C++交

原因如下:
在这里插入图片描述
  After a long lasting war on words, a war on arms finally breaks out between littleken’s and KnuthOcean’s kingdoms. A sudden and violent assault by KnuthOcean’s force has rendered a total failure of littleken’s command network. A provisional network must be built immediately. littleken orders snoopy to take charge of the project.

  With the situation studied to every detail, snoopy believes that the most urgent point is to enable littenken’s commands to reach every disconnected node in the destroyed network and decides on a plan to build a unidirectional communication network. The nodes are distributed on a plane. If littleken’s commands are to be able to be delivered directly from a node A to another node B, a wire will have to be built along the straight line segment connecting the two nodes. Since it’s in wartime, not between all pairs of nodes can wires be built. snoopy wants the plan to require the shortest total length of wires so that the construction can be done very soon.

Input

  The input contains several test cases. Each test case starts with a line containing two integer N (N ≤ 100), the number of nodes in the destroyed network, and M (M ≤ 104), the number of pairs of nodes between which a wire can be built. The next N lines each contain an ordered pair xi and yi, giving the Cartesian coordinates of the nodes. Then follow M lines each containing two integers i and j between 1 and N (inclusive) meaning a wire can be built between node i and node j for unidirectional command delivery from the former to the latter. littleken’s headquarter is always located at node 1. Process to end of file.

Output

  For each test case, output exactly one line containing the shortest total length of wires to two digits past the decimal point. In the cases that such a network does not exist, just output ‘poor snoopy’.

Sample Input

4 60 64 60 07 201 21 32 33 43 13 24 30 01 00 11 21 34 12 3

Sample Output

31.19poor snoopy

代码:

#include 
#include
int n, m;double flag;struct node { int be, en; double va;}a[10010];double zhuliu(int root) { int pre[101], consume[101], vis[101], i; double sum = 0, dis[101]; while (true) { for (i = 1; i <= n; i++)dis[i] = flag; for (i = 1; i <= m; i++) if (a[i].be != a[i].en && a[i].va < dis[a[i].en]) pre[a[i].en] = a[i].be, dis[a[i].en] = a[i].va; for (i = 1; i <= n; i++) { if (i != root && dis[i] == flag)return -1; vis[i] = consume[i] = 0; } int cnt = 0; for (i = 1; i <= n; i++) { if (i == root)continue; sum += dis[i]; int v = i; while (vis[v] != i && v != root && !consume[v]) vis[v] = i, v = pre[v]; if (!consume[v] && v != root) { consume[v] = ++cnt; for (int u = pre[v]; u != v; u = pre[u]) consume[u] = cnt; } } if (!cnt)return sum; for (i = 1; i <= n; i++) if (!consume[i])consume[i] = ++cnt; for (i = 1; i <= m; i++) { int u = a[i].be; int v = a[i].en; a[i].be = consume[u]; a[i].en = consume[v]; if (consume[u] != consume[v])a[i].va -= dis[v]; } root = consume[root]; n = cnt; }}double calculate(double a, double b, double c, double d) { return sqrt((a - b) * (a - b) + (c - d) * (c - d));}int main() { while (~scanf("%d %d", &n, &m)) { double x[101], y[101]; flag = 1; int i; for (i = 1; i <= n; i++)scanf("%lf %lf", &x[i], &y[i]); for (i = 1; i <= m; i++) { scanf("%d %d", &a[i].be, &a[i].en); a[i].va = calculate(x[a[i].be], x[a[i].en], y[a[i].be], y[a[i].en]); flag += a[i].va; } double re = zhuliu(1); if (re == -1)printf("poor snoopy\n"); else printf("%.2lf\n", re); }}

转载地址:http://qqvo.baihongyu.com/

你可能感兴趣的文章
MSCRM调用外部JS文件
查看>>
MSCRM调用外部JS文件
查看>>
MSEdgeDriver (Chromium) 不适用于版本 >= 79.0.313 (Canary)
查看>>
MsEdgeTTS开源项目使用教程
查看>>
msf
查看>>
MSSQL数据库查询优化(一)
查看>>
MSSQL数据库迁移到Oracle(二)
查看>>
MSSQL日期格式转换函数(使用CONVERT)
查看>>
MSTP多生成树协议(第二课)
查看>>
MSTP是什么?有哪些专有名词?
查看>>
Mstsc 远程桌面链接 And 网络映射
查看>>
Myeclipse常用快捷键
查看>>
MyEclipse更改项目名web发布名字不改问题
查看>>
MyEclipse用(JDBC)连接SQL出现的问题~
查看>>
mt-datetime-picker type="date" 时间格式 bug
查看>>
myeclipse的新建severlet不见解决方法
查看>>
MyEclipse设置当前行背景颜色、选中单词前景色、背景色
查看>>
Mtab书签导航程序 LinkStore/getIcon SQL注入漏洞复现
查看>>
myeclipse配置springmvc教程
查看>>
MyEclipse配置SVN
查看>>