PAT--1114. Family Property(并查集)

题解

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <vector>
#include <stack>
using namespace std;

const int maxn = 10005;
struct Person{
int m_esate;
int area;
};
struct Ans_info{
int id, m;
double avg_sets, avg_area;
};
Person p_info[maxn];
int p[maxn];
bool flag[maxn];
int n;

int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
void Union(int x, int y){
x = find(x), y = find(y);
if(x != y){
p[x] = y;
}
}

int main(){
#ifndef ONLINE_JUDGE
freopen("data.in", "r", stdin);
#endif // ONLINE_JUDGE

for(int i = 0; i < maxn; ++i) p[i]= i;

cin >> n;
int id, f_id, m_id, k, kid;
for(int i = 0; i < n; ++i){
cin >> id >> f_id >> m_id >> k;
flag[id] = flag[f_id] = flag[m_id] = true;
if(f_id != -1) Union(id, f_id);
if(m_id != -1) Union(id, m_id);
for(int j = 0; j < k; ++j){
cin >> kid;
flag[kid] = true;
Union(id, kid);
}
cin >> p_info[id].m_esate >> p_info[id].area;
}
// the root id of every family
vector<int> roots;
for(int i = 0; i < maxn; ++i){
if(flag[i] && find(i) == i) roots.push_back(i);
}
vector<Ans_info> vec;
for(auto root : roots){
int tot_esate = 0, tot_area = 0, tot_m = 0;
id = root;
for(int i = 0; i < maxn; ++i){
// if i is the member of the family
if(flag[i] && find(i) == root){
id = min(id, i);
tot_m++;
tot_area += p_info[i].area;
tot_esate += p_info[i].m_esate;
}
}
vec.push_back(Ans_info{id, tot_m, 1.0*tot_esate/tot_m, 1.0*tot_area/tot_m});
}

sort(vec.begin(), vec.end(), [](Ans_info a1, Ans_info a2){
if(a1.avg_area != a2.avg_area) return a1.avg_area > a2.avg_area;
return a1.id < a2.id;
});

cout<< vec.size() << endl;
for(int i = 0; i < vec.size(); ++i){
printf("%04d %d %.3f %.3f\n", vec[i].id, vec[i].m, vec[i].avg_sets, vec[i].avg_area);
}
return 0;
}