HDU 4562 守护雅典娜

const int N=1005;


class point
{
    public:
    int x,y;


    point(){}
    point(int _x,int _y)
    {
        x=_x;
        y=_y;
    }
    void get()
    {
        RD(x,y);
    }


    point operator-(point a)
    {
        return point(x-a.x,y-a.y);
    }


    int len()
    {
        return x*x+y*y;
    }
};




class Circle
{
    public:
    point p;
    int R;


    void get()
    {
        p.get();
        RD(R);
    }


    int on(point a)
    {
        return R*R==(a-p).len();
    }


    int in(point a)
    {
        return R*R>(a-p).len();
    }


    int ok(Circle a)
    {
        int x=abs(a.R-R),y=a.R+R,L=(a.p-p).len();
        return L<x*x||L>y*y;
    }
};




point a,b;
vector<Circle> p,q;
int n,f1[N],f2[N];


int cmp(Circle a,Circle b)
{
    return a.R<b.R;
}


int DP()
{
    sort(p.begin(),p.end(),cmp);
    sort(q.begin(),q.end(),cmp);
    int ans=0,i,j;
    FOR0(i,SZ(p))
    {
        f1[i]=0;
        FOR0(j,i) if(p[i].ok(p[j])) f1[i]=max(f1[i],f1[j]);
        f1[i]++;
        ans=max(ans,f1[i]);
    }
    FOR0(i,SZ(q))
    {
        f2[i]=0;
        FOR0(j,i) if(q[i].ok(q[j])) f2[i]=max(f2[i],f2[j]);
        f2[i]++;
        ans=max(ans,f2[i]);
    }
    FOR0(i,SZ(p)) FOR0(j,SZ(q)) if(p[i].ok(q[j]))
    {
        ans=max(ans,f1[i]+f2[j]);
    }
    return ans;
}


int main()
{
    int num=0;
    rush()
    {
        RD(n); b.get();
        a=point(0,0);
        Circle t;
        int i;
        p.clear(); q.clear();
        FOR0(i,n)
        {
            t.get();
            if(t.on(a)||t.on(b)) continue;
            if(t.in(a)&&!t.in(b)) p.pb(t);
            if(!t.in(a)&&t.in(b)) q.pb(t);
        }
        printf("Case %d: ",++num);
        PR(DP());
    }
}