重温一下前几天的一个题,放松一下放松一下,今天大家都太强了QAQ
1107. Social Clusters (30)
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 (<=1000), 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 (>0) is the number of hobbies, and hi[j] 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: 4Sample Output:
3 4 3 1
题意:给个N,有N个人,接下来按编号1~N的顺序,每行给出一个人的感兴趣的活动,先给个K,表示K个活动,然后引号后面有K个活动编号,表示这个人喜欢这个活动。如果有两个人有任意重叠的喜欢的活动,它们就是一个小圈子的,要求输出有几个小圈子,接下来降序输出每个小圈子有几个人。
思路:并查集大法(千万不要一边读一边合并,不知道为啥一边读一边合并有三个测试点就是过不去,惆怅)↓
#include<cstdio> #include<cmath> #include<algorithm> #include<cstring> #include<iostream> using namespace std; const int maxv = 1111; int fa[maxv],root[maxv]; int findfa(int x)//找爸爸 { int a=x; while(x!=fa[x]) { x=fa[x]; } while(a!=fa[a]) { int z=a; a=fa[a]; fa[z]=x; } return x; } void uni(int a,int b)//合并两个小朋友 { int faa=findfa(a); int fab=findfa(b); if(faa!=fab) { fa[faa]=fab; } } struct node { int num;//喜欢该活动的人数 int a[maxv];//喜欢该活动的人的编号 }act[maxv]; int N,K,temp; int main() { scanf("%d",&N); for(int i=1;i<=N;i++) { fa[i]=i; } for(int i=1;i<=N;i++) { scanf("%d:",&K); for(int j=1;j<=K;j++) { scanf("%d",&temp); act[temp].a[++act[temp].num]=i; } } for(int i=1;i<maxv;i++) { for(int j=2;j<=act[i].num;j++) { uni(act[i].a[1],act[i].a[j]); } } for(int i=1;i<=N;i++) { root[findfa(i)]++; } int co=0; for(int i=1;i<=N;i++) { if(root[i]>0) co++; } printf("%d\n",co); sort(root+1,root+1+N); for(int i=N;i>N-co;i--) { if(i==N) printf("%d",root[i]); else printf(" %d",root[i]); } return 0; }