When register on a social network, you are always asked to specify your hobbies in order to find some potential friends with the same hobbies. A social cluster is a set of people who have some of their hobbies in common. You are supposed to find all the clusters.
Input Specification:
Each input file contains one test case. For each test case, the first line contains a positive integer N (≤), the total number of people in a social network. Hence the people are numbered from 1 to N. Then N lines follow, each gives the hobby list of a person in the format:
Ki: hi[1] hi[2] ... hi[Ki]
where Ki (>) is the number of hobbies, and [ is the index of the j-th hobby, which is an integer in [1, 1000].
Output Specification:
For each case, print in one line the total number of clusters in the network. Then in the second line, print the numbers of people in the clusters in non-increasing order. The numbers must be separated by exactly one space, and there must be no extra space at the end of the line.
Sample Input:
8 3: 2 7 10 1: 4 2: 5 3 1: 4 1: 3 1: 4 4: 6 8 1 5 1: 4
Sample Output:
3 4 3 1
思路:
- 在每次输入个人的一个爱好后,都可能对如今的社交网络产生变化,故都需要在此时进行合并操作
- father数组在初始保存的根节点都是自己,表示自己是一个单独的社交网络
- 这里因为每个人可能有不止一个爱好,故还需辅助数组hobby,记录任何一个有该爱好的人,之后再与当前读入的人合并根节点即可
#include<cstdio> #include<algorithm> using namespace std; const int maxn=1010; int father[maxn]={0}; int isRoot[maxn]={0}; int hobby[maxn]={0}; int n,num,temp; int findFather(int x){ if(father[x]==x) return x; else{ father[x]=findFather(father[x]); return father[x]; } } void Union(int a,int b){ int faA=findFather(a); int faB=findFather(b); if(faA!=faB) father[faA]=faB; } bool cmp(int a,int b){ return a>b; } int main(){ scanf("%d",&n); for(int i=1;i<=n;i++) father[i]=i; for(int i=1;i<=n;i++){ scanf("%d:",&num); for(int j=0;j<num;j++){ scanf("%d",&temp); if(hobby[temp]==0) hobby[temp]=i; Union(i,hobby[temp]); } } for(int i=1;i<=n;i++){ isRoot[findFather(i)]++;//此处不能用father[i],可能存在嵌套关系 } int ans=0; for(int i=1;i<=n;i++) if(isRoot[i]!=0) ans++; printf("%d\n",ans); sort(isRoot+1,isRoot+n+1,cmp); for(int i=1;i<=ans;i++){ printf("%d",isRoot[i]); if(i<ans) printf(" "); } return 0; }