1114 Family Property (25 分)

考察并查集的熟练使用。

const int N=10010;
struct Node
{
    int id;
    int father,mother;
    int k;
    int child[6];
}a[1010];
struct Answer
{
    int id;
    int cnt;
    double sets;
    double area;
    bool operator<(const Answer &W) const
    {
        if(area != W.area) return area > W.area;
        return id < W.id;
    }
};
int p[N],cnt[N];
double sets[N],area[N];
bool vis[N];
int n;

int find(int x)
{
    if(x != p[x]) p[x]=find(p[x]);
    return p[x];
}

void merge(int x,int y)
{
    int px=find(x),py=find(y);
    if(px < py) swap(px,py);
    if(px != py)
    {
        p[px]=py;
        cnt[py]+=cnt[px];
        sets[py]+=sets[px];
        area[py]+=area[px];
    }
}

int main()
{
    for(int i=0;i<N;i++) p[i]=i,cnt[i]=1;

    cin>>n;

    for(int i=0;i<n;i++)
    {
        cin>>a[i].id>>a[i].father>>a[i].mother;

        cin>>a[i].k;
        for(int j=0;j<a[i].k;j++) cin>>a[i].child[j];
        cin>>sets[a[i].id]>>area[a[i].id];
    }

    for(int i=0;i<n;i++)
    {
        vis[a[i].id]=true;
        if(~a[i].father)
        {
            vis[a[i].father]=true;
            merge(a[i].id,a[i].father);
        }
        if(~a[i].mother)
        {
            vis[a[i].mother]=true;
            merge(a[i].id,a[i].mother);
        }

        for(int j=0;j<a[i].k;j++)
        {
            vis[a[i].child[j]]=true;
            merge(a[i].id,a[i].child[j]);
        }
    }

    int tot=0;
    vector<Answer> res;
    for(int i=0;i<N;i++)
        if(vis[i] && p[i] == i)
        {
            tot++;
            res.pb({i,cnt[i],sets[i]/cnt[i],area[i]/cnt[i]});
        }

    sort(res.begin(),res.end());

    cout<<tot<<endl;
    for(int i=0;i<res.size();i++)
    {
        int id=res[i].id;
        printf("%04d %d %.3f %.3f
",id,cnt[id],sets[id]/cnt[id],area[id]/cnt[id]);
    }

    //system("pause");
    return 0;
}