POJ3041 二分图最大匹配

 1 //Memory: 1260K        Time: 47MS
 2 #include <iostream>
 3 using namespace std;
 4 
 5 int map[501][501];
 6 bool visit[10002];
 7 int match[10002];
 8 int n;
 9 
10 bool path(int start)
11 {
12     int i;
13     
14     for ( i = 1; i <= n; i++ )
15     {
16         if ( map[start][i] && !visit[i] ){
17             visit[i] = true;
18             if ( match[i] == -1 || path(match[i]) )
19             {
20                 match[i] = start;
21                 return true;
22             }
23         }
24     }
25     return false;
26 }
27 
28 int main()
29 {
30     int k,i;
31     int x,y;
32     int result;
33     
34     memset(match,-1,sizeof(match));
35     memset(map,0,sizeof(map));
36     cin >> n >> k;
37     for ( i = 1; i <= k; i++ )
38     {
39         cin >> x >> y;
40         map[x][y] = 1;
41     }
42     result = 0;
43     for ( i = 1; i <= n; i++ )
44     {
45         memset(visit,false,sizeof(visit));
46         if (path(i))
47             result++;
48     }
49     cout << result << endl;
50     return 0;
51 }