杭电1301Jungle Roads
2015-08-11 17:52
309 查看
Jungle Roads
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5421 Accepted Submission(s): 3909
Problem Description
The Head Elder of the tropical island of Lagrishan has a problem. A burst of foreign aid money was spent on extra roads between villages some years ago. But the jungle overtakes roads relentlessly, so the large road network is too expensive to maintain. The
Council of Elders must choose to stop maintaining some roads. The map above on the left shows all the roads in use now and the cost in aacms per month to maintain them. Of course there needs to be some way to get between all the villages on maintained roads,
even if the route is not as short as before. The Chief Elder would like to tell the Council of Elders what would be the smallest amount they could spend in aacms per month to maintain roads that would connect all the villages. The villages are labeled A through
I in the maps above. The map on the right shows the roads that could be maintained most cheaply, for 216 aacms per month. Your task is to write a program that will solve such problems.
The input consists of one to 100 data sets, followed by a final line containing only 0. Each data set starts with a line containing only a number n, which is the number of villages, 1 < n < 27, and the villages are labeled with the first n letters of the alphabet,
capitalized. Each data set is completed with n-1 lines that start with village labels in alphabetical order. There is no line for the last village. Each line for a village starts with the village label followed by a number, k, of roads from this village to
villages with labels later in the alphabet. If k is greater than 0, the line continues with data for each of the k roads. The data for each road is the village label for the other end of the road followed by the monthly maintenance cost in aacms for the road.
Maintenance costs will be positive integers less than 100. All data fields in the row are separated by single blanks. The road network will always allow travel between all the villages. The network will never have more than 75 roads. No village will have more
than 15 roads going to other villages (before or after in the alphabet). In the sample input below, the first data set goes with the map above.
The output is one integer per line for each data set: the minimum cost in aacms per month to maintain a road system that connect all the villages. Caution: A brute force solution that examines every possible set of roads will not finish within the one minute
time limit.
Sample Input
9
A 2 B 12 I 25
B 3 C 10 H 40 I 8
C 2 D 18 G 55
D 1 E 44
E 2 F 60 G 38
F 0
G 1 H 35
H 1 I 35
3
A 2 B 10 C 40
B 1 C 20
0
Sample Output
216
30
Source
Mid-Central USA 2002
题意很好理解的,也是最小生成树,模板题。
附ac代码:
#include<stdio.h> #include<string.h> #include<algorithm> using namespace std; struct node { char start; char end; int cost; } t[10010]; int cmp(node a,node b) { return a.cost <b.cost ; } int per[110]; int find(char c)//定成字符型,比较方便; { char s=c; while(s!=per[s]) s=per[s]; return s; } int join(char x,char y) { char fx=find(x); char fy=find(y); if(fx!=fy) { per[fx]=fy; return 1; } return 0; } int m,n,k,a[100],dis; char c,ch; int main() { while(scanf("%d",&n),n) { getchar(); for(int i=0;i<100;i++) per[i]=i; int js=0; for(int i=1;i<n;i++) { scanf("%c %d",&c,&m); getchar(); for(int j=1;j<=m;j++) { scanf("%c %d",&ch,&dis); getchar(); t[js].start=c; t[js].end=ch; t[js].cost=dis; js++; } } sort(t,t+js,cmp); int sum=0; for(int i=0;i<js;i++) { if(join(t[i].start,t[i].end)) sum=sum+t[i].cost ; } printf("%d\n",sum); } return 0; }
相关文章推荐
- 详解图的应用(最小生成树、拓扑排序、关键路径、最短路径)
- 最小生成树算法之Prim算法
- 最小生成树算法——Prim和Kruskal算法的实现
- Data Structure - Week 15
- HDU-1213-How Many Tables
- Longest Consecutive Sequence,Distinct Subsequences,Interleaving String,Scramble String
- poj 2485 Highways
- SARS病毒传染 并查集
- Kruskal 最小生成树
- 最小生成树
- HDU 1213
- 杭电1870 愚人节的礼物
- CSU1307 并查集+SPFA
- 关于杭电1405 The Last Practice 的问题
- hdu-1103 模拟题。
- hdu-1022 栈的应用。
- hdu-1247 简单map的应用。(字典树)
- hdu-1251 字典树公共前缀。
- hdu-1075 map映射表的应用。
- 杭电1004