Poj 1325 Machine Schedule [minimum vertex overwrite]

E-Machine Schedule Time limit:1000 ms Memory limit:10000kb 64bit Io format:% I64d & % i64usubmit status practice poj 1325 appoint description: System crawler)

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 particle 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.

Obviusly, 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 invocations. 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 shoshould be one integer per line, which means the minimal times of restarting machine.

Sample Input

5 5 100 1 11 1 22 1 33 1 44 2 15 2 26 2 37 2 48 3 39 4 30

Sample output

3
The reason why I stick the question down is that I did not carefully read the question once.
Note:
There are two machines in N and M modes, respectively. At the beginning, all machines are in 0 mode.
It tells you that some tasks can be completed in X1 mode of the first machine or X2 mode of the second machine.
In addition, the switch mode of each machine needs to be restarted.
How many times can I restart at least?

Analysis:
The left and right sets are in two machine modes.
The edge is a task.
You only need to select the least vertex to overwrite all edges.
Note that at first the 0 Mode
So you only need to create no edge for 0.
Network streams can also be used

Code:

#include <iostream>#include <cstdio>#include <cstring>#include <vector>using namespace std;const int maxn = 105;int n;vector<int> G[maxn];int vis[maxn];int Link[maxn];bool Find(int u) {    for(int i = 0; i < G[u].size(); i++) {        int v = G[u][i];        if(!vis[v]) {            vis[v] = 1;            if(Link[v] == -1 || Find(Link[v])) {                Link[v] = u;                return true;            }        }    }    return false;}int solve() {    int cnt = 0;    memset(Link, -1, sizeof(Link));    for(int i = 0; i < n; i++) {        memset(vis, 0, sizeof(vis));        if(Find(i)) cnt++;    }    return cnt;}int main() {    int m, k;    int a, b, c;    while(scanf("%d",&n) && n) {        scanf("%d %d",&m, &k);        n = max(n, m);        for(int i = 0; i < n; i ++) G[i].clear();        for(int i = 0; i < k; i++) {            scanf("%d %d %d",&a, &b, &c);            if(b == 0 || c == 0) continue;            G[b].push_back(c);        }        printf("%d\n",solve());    }    return 0;}

View code