PAT 1114 Family Property (并查集)

#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;
#define m 10000
int road[m],n;
struct item{//先合并item，才能统计
int id,h,area;
}d[1010];
int mem[m];//family mem
struct family{
int minid;
double avearea, avehouse;
}f[m];//打表
bool cmp(family a,family b){
if(a.avearea!=b.avearea) return a.avearea>b.avearea;
else return a.minid<b.minid;
}
int getroot(int x){
if(road[x]==x)
return x;
else{
int root=getroot(road[x]);
road[x]=root;
return root;
}
}
void merge(int x,int y){
int u=getroot(x);
int v=getroot(y);
if(u<v){//u为根
road[v]=u;
mem[u]+=mem[v];
}else if(u>v){
road[u]=v;
mem[v]+=mem[u];
}
}
void init(){
for (int i = 0; i < m; i++){
mem[i]=1;
road[i]=i;
}
}
int main(){
init();
cin>>n;
int id,fid,mid,k;
for (int i = 0; i < n; i++){
scanf("%d%d%d%d",&id,&fid,&mid,&k);
d[i].id=id;
if(fid!=-1)
merge(id,fid);
if(mid!=-1)
merge(id,mid);
for (int j = 0; j < k; j++){
int t;
scanf("%d",&t);
merge(t,id);
}
scanf("%d%d",&d[i].h,&d[i].area);
}
for (int i = 0; i < m; i++)
getroot(i);
set<int> ansid;
for (int i = 0; i < n; i++){
int root=getroot(d[i].id);
if(ansid.count(root)){
f[root].avearea+=d[i].area;
f[root].avehouse+=d[i].h;
}else{
f[root].minid=root;
f[root].avearea=d[i].area;
f[root].avehouse=d[i].h;
ansid.insert(root);
}
}
vector<family> ans;
for(set<int>::iterator it=ansid.begin();it!=ansid.end();it++){
int t=*it;
f[t].avearea=f[t].avearea*1.0/mem[t];
f[t].avehouse=f[t].avehouse*1.0/mem[t];
ans.push_back(f[t]);
}
sort(ans.begin(),ans.end(),cmp);
printf("%d\n",ans.size());
for (int i = 0; i < ans.size(); i++)
printf("%.4d %d %.3lf %.3lf\n",ans[i].minid,mem[ans[i].minid],ans[i].avehouse,ans[i].avearea);
return 0;
}