学步园

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
#define MAX 200
int g[MAX][MAX],vis[MAX],link[MAX];
int k,n,m,xx;
int dfs(int x){
    for(int i = 1;i <= xx;i++){
        if(g[x][i] == 1 && vis[i] == 0){
            vis[i] = 1;
            if(link[i] == -1 || dfs(link[i])){
                link[i] = x;
                return 1;
            }
        }
    }
    return 0;
}
int main(){
    int x,y;
    scanf("%d",&k);
    while(k--){
        memset(g,0,sizeof(g));
        memset(link,-1,sizeof(link));
        scanf("%d%d",&n,&m);
        for(int i = 1;i <= m;i++){
            scanf("%d%d",&x,&y);
            g[x][y] = 1;
        }
        xx = n>m?n:m;
        int ans = 0;
        for(int i = 1;i <= xx;i++){
            memset(vis,0,sizeof(vis));
            if(dfs(i)) ans++;
        }
        n -= ans;
        cout<<n<<endl;
    }
    return 0;
}