POJ3041-Asteroids-匈牙利算法

 1 #include <stdio.h>
 2 #include <math.h>
 3 #include <string.h>
 4 #include <stdlib.h>
 5 #include <iostream>
 6 #include <sstream>
 7 #include <algorithm>
 8 #include <string>
 9 #include <queue>
10 #include <ctime>
11 #include <vector>
12 using namespace std;
13 const int maxn= 25;
14 const int maxm=500+10;
15 const int inf = 0x3f3f3f3f;
16 typedef long long ll;
17 int n,m;
18 int match[maxm];
19 bool visited[maxm];
20 bool mp[maxm][maxm];
21 bool Find(int x){
22     for(int i=1;i<=n;i++){
23         if(mp[x][i]&&visited[i]==0){
24             visited[i]=true;
25             if(match[i]==0||Find(match[i])){
26                 match[i]=x;
27                 return true;
28             }
29         }
30     }
31     return false;
32 }
33 int main(){
34     int x,y,num;
35     while(~scanf("%d%d",&n,&m)){
36         memset(mp,0,sizeof(mp));
37         memset(match,0,sizeof(match));
38         memset(visited,0,sizeof(visited));
39         for(int i=0;i<m;i++){
40             scanf("%d%d",&x,&y);
41             mp[x][y]=true;
42         }
43         num=0;
44         for(int i=1;i<=n;i++){
45             memset(visited,0,sizeof(visited));
46             if(Find(i))num++;
47         }
48         printf("%d\n",num);
49     }
50     return 0;
51 }