感冒病毒 suspects 并查集

来源：互联网发布：js调用json接口数据编辑：程序博客网时间：2024/05/03 12:27

题目大意：给定n个人，m个团，同一个团中只要有一个人感染病毒整个团就都感染病毒。现在0号感染了病毒，问总共有多少个人会感染病毒。

题目分析：简单的并查集。

#include<cstdio>#include<cstdlib>#include<cstring>#include<iostream>#include<algorithm>#include<functional>#include<cmath>#include<cctype>#include<cassert>#include<climits>using namespace std;#define For(i,n) for(int i=1;i<=n;i++)#define Rep(i,n) for(int i=0;i<n;i++)#define Fork(i,k,n) for(int i=k;i<=n;i++)#define ForD(i,n) for(int i=n;i;i--)#define Forp(x) for(int p=pre[x];p;p=next[p])#define RepD(i,n) for(int i=n;i>=0;i--)#define MEM(a) memset(a,0,sizeof(a))#define MEMI(a) memset(a,127,sizeof(a))#define MEMi(a) memset(a,128,sizeof(a))#define INF (2139062143)#define phiF (1000000006)#define MAXN (1000000+10)typedef long long LL;int fa[30005],n,m,k,x,y,fx,fy;int get(int v){if (fa[v]!=v) fa[v]=get(fa[v]);return fa[v];}int main(){scanf("%d%d",&n,&m);Fork (i,0,n) fa[i]=i;For (i,m) {scanf("%d",&k);if (k){scanf("%d",&x);For (j,k-1){scanf("%d",&y);int fx,fy;fx=get(x);fy=get(y);if (fx!=fy) fa[fx]=fy;}}}fx=get(0);int ans=1;For (i,n) {fy=get(i);if (fx==fy) ans++;}printf("%d",ans);}

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