1107. Social Clusters (30)

时间限制

1000 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

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:

K_i: h_i[1] h_i[2] ... h_i[K_i]

where K_i (>0) is the number of hobbies, and h_i[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:

83: 2 7 101: 42: 5 31: 41: 31: 44: 6 8 1 51: 4

Sample Output:

34 3 1

参照算法笔记P311.

没有好好理解并查集。

这里应该考虑爱好相同时，把人并起来，而不是爱好。

#include<stdio.h>#include<algorithm>using namespace std;bool comp(int a,int b){return a>b;}int course[1010]={0};int tree[1010];int cnt[1010]={0};int findroot(int x){if(tree[x]==-1)return x;return tree[x]=findroot(tree[x]);}void init(int n){int i;for(i=1;i<=n;i++){tree[i]=-1;}}int main(){int n,i,j,k,temp;scanf("%d",&n);init(n);for(i=1;i<=n;i++){scanf("%d:",&k);for(j=0;j<k;j++){scanf("%d",&temp);if(course[temp]==0){course[temp]=i;}else{int a=findroot(i);int b=findroot(course[temp]);if(a!=b){tree[a]=b;}}}}int cou=0;for(i=1;i<=n;i++){int index=findroot(i);cnt[index]++;if(tree[i]==-1){cou++;}}sort(cnt+1,cnt+1+n,comp);printf("%d\n",cou);printf("%d",cnt[1]);for(i=2;i<=cou;i++){printf(" %d",cnt[i]);}}