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*HDU1150 二分图

2024-08-21 04:18:43   224人阅读

Machine Schedule

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 8404    Accepted Submission(s): 4215


Problem Description
As we all know, machine scheduling is a very classical problem in computer science and has been studied for a very long history. Scheduling problems differ widely in the nature of the constraints that must be satisfied and the type of schedule desired. Here we consider a 2-machine scheduling problem.

There are two machines A and B. Machine A has n kinds of working modes, which is called mode_0, mode_1, …, mode_n-1, likewise machine B has m kinds of working modes, mode_0, mode_1, … , mode_m-1. At the beginning they are both work at mode_0.

For k jobs given, each of them can be processed in either one of the two machines in particular mode. For example, job 0 can either be processed in machine A at mode_3 or in machine B at mode_4, job 1 can either be processed in machine A at mode_2 or in machine B at mode_4, and so on. Thus, for job i, the constraint can be represent as a triple (i, x, y), which means it can be processed either in machine A at mode_x, or in machine B at mode_y.

Obviously, to accomplish all the jobs, we need to change the machine‘s working mode from time to time, but unfortunately, the machine‘s working mode can only be changed by restarting it manually. By changing the sequence of the jobs and assigning each job to a suitable machine, please write a program to minimize the times of restarting machines.
 

 

Input
The input file for this program consists of several configurations. The first line of one configuration contains three positive integers: n, m (n, m < 100) and k (k < 1000). The following k lines give the constrains of the k jobs, each line is a triple: i, x, y.

The input will be terminated by a line containing a single zero.
 

 

Output
The output should be one integer per line, which means the minimal times of restarting machine.
 

 

Sample Input
5 5 10 0 1 1 1 1 2 2 1 3 3 1 4 4 2 1 5 2 2 6 2 3 7 2 4 8 3 3 9 4 3 0
 

 

Sample Output
3
 

 

Source
Asia 2002, Beijing (Mainland China)
 
题意：
有两台机器，各有n和m个工作模式，k个任务，i x y,第i个任务可以由第一台机器的x模式执行或者第2台机器的y模式执行，每个机器如果换了一个模式就要重新启动，问最少的重启次数，最开始都在0模式
从零模式开始不用启动即第一次不用启动。
代码：
 1 // 最小点覆盖模板  一个模式可以同时执行多个任务。这就是最小点覆盖掉所有的边。
 2 #include<iostream>
 3 #include<cstdio>
 4 #include<cstring>
 5 using namespace std;
 6 int mp[102][102],vis[102],link[102];
 7 int n,Mu,Mv,m,k;
 8 int dfs(int x)
 9 {
10     for(int i=1;i<Mv;i++)
11     {
12         if(!vis[i]&&mp[x][i])
13         {
14             vis[i]=1;
15             if(link[i]==-1||dfs(link[i]))
16             {
17                 link[i]=x;
18                 return 1;
19             }
20         }
21     }
22     return 0;
23 }
24 int Maxcon()
25 {
26     int ans=0;
27     memset(link,-1,sizeof(link));
28     for(int i=1;i<Mu;i++)
29     {
30         memset(vis,0,sizeof(vis));
31         if(dfs(i)) ans++;
32     }
33     return ans;
34 }
35 int main()
36 {
37     int a,b,c;
38     while(scanf("%d",&n)&&n)
39     {
40         scanf("%d%d",&m,&k);
41         memset(mp,0,sizeof(mp));
42         while(k--){
43             scanf("%d%d%d",&c,&a,&b);
44             if(a!=0&&b!=0) mp[a][b]=1;  //0模式不用
45         }
46         Mu=n;Mv=m;      //左右集合
47         printf("%d\n",Maxcon());
48     }
49     return 0;
50 }

 

*HDU1150 二分图


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