SPOJ - UOFTCG 树的最小路径覆盖

//SPOJ - UOFTCG 树的最小路径覆盖

#include <bits/stdc++.h>
#include <vector>
using namespace std;
#define ll long long
const int mod = 1e9+7;
const int maxn=510;
const int N = 1e5+10;
int cnt;
int head[N];
struct edge{
    int to,next;
}e[N<<2];
void addedge(int u,int v){
    e[cnt].to=v,e[cnt].next=head[u],head[u]=cnt++;
    e[cnt].to=u,e[cnt].next=head[v],head[v]=cnt++;
}

int cov[N];
bool vis[N],used[N];
void dfs(int u,int f){
    used[u]=1;
    cov[u]=1;
    int tot=0;
    for(int i=head[u];~i;i=e[i].next){
        int v=e[i].to;
        if(v==f) continue;
        dfs(v,u);
        cov[u]+=cov[v];
        if(!vis[v]) tot++;
    }
    if(tot>=2) cov[u]-=2,vis[u]=1;
    else if(tot==1) cov[u]-=1;
}
int main(){
    // freopen("in.txt","r",stdin);
    int T;
    scanf("%d",&T);
    while(T--){
        cnt=0;
        memset(used,false,sizeof(used));
        memset(head,-1,sizeof(head));
        memset(cov,0,sizeof(cov));
        memset(vis,false,sizeof(vis));
        int n,m;
        scanf("%d%d",&n,&m);
        for(int i=1;i<=m;i++){
            int u,v;
            scanf("%d%d",&u,&v);
            addedge(u,v);
        }
        int ans=0;
        for(int i=1;i<=n;i++){
           if(!used[i]) dfs(i,0),ans+=cov[i];
        }
        // cout<<cov[1]<<endl;
        printf("%d\n",ans+n-1);
    }
}