POJ1611 The Suspects 并查集

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没什么好说的，建立n的并查集，把每个group的人都连起来，最后遍历一遍即可。

#include<iostream>#include<cstdio>#include<cstring>#include<ctime>#include<algorithm>#include<cstdlib>#include<cmath>#include<set>#include<bitset>#include<map>#include<stack>#include<queue>#include<vector>#include<utility>#define INF 0x3f3f3f3f#define inf 2*0x3f3f3f3f#define llinf 1000000000000000000#define pi acos(-1.0)#define mod 1000000007#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1#define lrt rt<<1#define rrt rt<<1|1#define rep(i,a,b) for(int i=(a);i<(b);i++)#define per(i,a,b) for(int i=(b)-1;i>=(a);i--)#define mem(a,b) memset(a,b,sizeof(a))#define lowbit(x) (x&-x)#define gi(x) scanf("%d",&x)#define gll(x) scanf("%lld",&x)#define gc(x) scanf("%c",&x)using namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair<int,int>P;/***********************************************/int par[30005],ranks[30005],sta[30005],up,n,m;void init(int n){    rep(i,0,n)par[i]=i,ranks[i]=0;}int finds(int x){    if(par[x]==x)return x;    return par[x]=finds(par[x]);}void unite(int x,int y){    x=finds(x);y=finds(y);    if(x==y)return ;    if(ranks[x]<ranks[y])par[x]=y;    else par[y]=x;    if(ranks[x]==ranks[y])ranks[x]++;}bool same(int x,int y){    return finds(x)==finds(y);}int main(){    while(scanf("%d%d",&n,&m))    {        init(n);        if(n==0&&m==0)break;        int k,x;        rep(i,0,m)        {            gi(k);up=0;            rep(j,0,k)            {                gi(x);                if(up!=0)unite(sta[up-1],x);                sta[up++]=x;            }        }        int cnt=0;        rep(i,0,n)if(same(i,0))cnt++;        printf("%d\n",cnt);    }    return 0;}

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