Machine Schedule

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 6339    Accepted Submission(s): 3178

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)

题目大意：

每个项目可以由A或者B来单独完成，但是不同的任务的需要的A或者Ｂ不同，求重启的最小次数

考察知识点：匈牙利算法模板

//考察的知识点：匈牙利算法
//考查知识点：匈牙利算法模板题
/********************************************************************
    int find(int x)
    {
        int j;
        for(j=1;j<m;++j)//逐次遍历每个女孩纸
        {
            if(line[x][j]&&!used[j])//彼此有暧昧且名花无主
            {
                used[j]=1;
                if(girl[j]==0||find(girl[j]))//名花无主或能够腾出来位置
                {
                    girl[j]=x;
                    return 1;//寻找到可配对的女孩纸
                }
            }
        }
        return 0;
    }
**********************************************************************/

#include<stdio.h>
#include<string.h>
int girl[110],used[110];
int line[110][110];
int n,m,k;
int find(int x)//匈牙利模板
{
	int j;
	for(j=1;j<=m;++j)
	{
		if(!used[j]&&line[x][j])
		{
			used[j]=1;
			if(!girl[j]||find(girl[j]))
			{
				girl[j]=x;
				return 1;
			}
		}
	}
	return 0;
}
int main()
{
	while(~scanf("%d",&n),n)
	{
		int a,b,c;
		memset(used,0,sizeof(used));
		memset(line,0,sizeof(line));
		memset(girl,0,sizeof(girl));
		scanf("%d%d",&m,&k);
		for(int i=1;i<=k;++i)
		{
			scanf("%d%d%d",&a,&b,&c);
			line[b][c]=1;
		}
		int count=0;
		for(int i=1;i<=n;++i)
		{
			memset(used,0,sizeof(used));
			if(find(i))
			{
				count++;
			}
		}
		printf("%d\n",count);
	}
	return 0;
}