题目大意：给定平面上的
爆搜T到死，，加什么剪枝都没用……
随机化大法好
每次随机一个序列，依次贪心加入，然后更新答案
据说很靠谱？反正写完直接过了
;typedef bitset<M> abcd;struct Point{int x,y;friend istream& operator >> (istream &_,Point &p){return scanf(“%d%d”,&p.x,&p.y),_;}< (const Point &p1,const Point &p2){return p1.x < p2.x ;}friend int Distance(const Point &p1,const Point &p2){return (p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y) ;}}points[M];int n,d;abcd a[M];abcd now,able,ans;int main(){int i,j;cin>>n>>d;for(i=1;i<=n;i++)cin>>points[i];for(i=1;i<=n;i++)for(j=i+1;j<=n;j++)if(Distance(points[i],points[j])<=d*d)a[i][j]=a[j][i]=true;static int order[M];for(i=1;i<=n;i++){able[i]=true;order[i]=i;}for(j=1;j<=1000;j++){abcd able=::able;now.reset();for(i=1;i<=n;i++)if(able[order[i]]){now[order[i]]=true;able&=a[order[i]];}if(now.count()>ans.count())ans=now;random_shuffle(order+1,order+n+1);}cout<<ans.count()<<endl;for(i=1;i<=n;i++)if(ans[i])printf(“%d “,i);return 0;}
家!甜蜜的家!天下最美好的莫过於家
