ZOJ 1525 air raid

Air Raid

#include <iostream>
#include <cstring>
using namespace std;
#define SIZE 150

int n;
int map[SIZE][SIZE];
int visited[SIZE];
int match[SIZE];

int Hungary(int u){		//hungary匈牙利
	int i;
	for(i = 1; i <= n; i++){
		if(!visited[i] && map[u][i]){
			visited[i] = 1;
			if(match[i] == 0 || Hungary(match[i])){
				match[i] = u;
				return 1;
			}
		}
	}
	return 0;
}

int main(){
	int iCase;
	int m, from, to, i;
	cin>>iCase;
	while(iCase--){
		memset(map, 0, sizeof(map));
		memset(match, 0, sizeof(match));
		cin>>n>>m;
		for(i = 0; i < m; i++){
			cin>>from>>to;
			map[from][to] = 1;
		}
		int ans = 0;
		for(i = 1; i <= n; i++){
			memset(visited, 0, sizeof(visited));
			if(Hungary(i))
				ans++;
		}
		cout<<n - ans<<endl;
	}
	return 0;
}