1114 Family Property（并查集）

Posted 2021-03-04 keep23456

题目：https://pintia.cn/problem-sets/994805342720868352/problems/994805356599820288 

题目比较麻烦，因为限时200ms，所以要用散列。

 1 #include<iostream>
 2 #include<vector>
 3 #include<unordered_map>
 4 #include<algorithm>
 5 using namespace std;
 6 
 7 struct Node {
 8     int id,num;
 9     double AVGS = 0,AVGA = 0;
10     bool flag = false;
11 };
12 
13 int father[10000];
14 void init() {
15     for(int i = 0; i < 10000; ++i)
16         father[i] = i;
17 }
18 
19 int findfather(int a) {
20     int b = a;
21     while(a != father[a])
22         a = father[a];
23     while(b != father[b]) {
24         int t = b;
25         b = father[b];
26         father[t] = a;
27     }
28     return a;
29 }
30 
31 void Union(int a,int b) {
32     int fa = findfather(a);
33     int fb = findfather(b);
34     if(fa != fb)
35         father[max(fa,fb)] = min(fa,fb);
36 }
37 bool cmp(const Node& a ,const Node& b) {
38     if(a.flag != b.flag) return a.flag > b.flag;
39     if(a.AVGA /a.num != b.AVGA/b.num ) return a.AVGA /a.num > b.AVGA/b.num;
40     return a.id < b.id;
41 }
42 
43 int main() {
44     init();
45     int n;
46     cin>>n;
47     unordered_map<int,vector<int> > mp1;//记录当前ID的信息
48     unordered_map<int,int> mp2; //记录所有ID
49     for(int i = 0; i < n; ++i) {
50         int id,fa,mo,k,child,estate,area;
51         scanf("%d%d%d%d",&id,&fa,&mo,&k);
52         mp2[id] = 1;
53         if(fa != -1) Union(id,fa),mp2[fa] = 1;
54         if(mo != -1) Union(id,mo),mp2[mo] = 1;
55         for(int j = 0; j < k; ++j) {
56             scanf("%d",&child);
57             Union(id,child);
58             mp2[child] = 1;
59         }
60         scanf("%d%d",&estate,&area);
61         mp1[id].push_back(estate);
62         mp1[id].push_back(area);
63     }
64     vector<Node> v(10000);
65     int cnt = 0;
66     for(auto it:mp2) {
67         int fa = findfather(it.first);
68         v[fa].id = fa;
69         v[fa].num++;
70         if(v[fa].num == 1) cnt++; //统计不同家庭的个数 
71         if(mp1.count(it.first)) {
72             v[fa].AVGS += mp1[it.first][0];
73             v[fa].AVGA += mp1[it.first][1];
74         }
75         v[fa].flag = true;
76     }
77     sort(v.begin(),v.end(),cmp);
78     printf("%d
",cnt);
79     for(int i = 0; i < cnt; ++i) {
80         printf("%04d %d %.3f %.3f
",v[i].id,v[i].num,v[i].AVGS/v[i].num,v[i].AVGA/v[i].num);
81     }
82     return 0;
83 }