【定径圆覆盖最多点模板】

最新推荐文章于 2022-06-24 12:37:59 发布

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最新推荐文章于 2022-06-24 12:37:59 发布 · 置顶 · 1.4k 阅读

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#struct

#define eps 1e-9
#define pi acos(-1.0)
#define N 222
struct point{
    double x,y;
}p[N];
struct alpha{
    double v;
    bool flag;
    bool friend operator <(const alpha &a,const alpha &b){//排序专用偏序关系
       return a.v < b.v;
    }
}alp[N * 2];

double dis(point a, point b){
    return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
}
int n;
void solve(double R){//传入定径圆的半径
    int ans = 0;
    double theta,phi,dist;
    for(int i = 0;i < n;i++){
       int k = 0;
       for(int j = 0;j < n;j++){
           if(i == j) continue;
           dist = dis(p[i],p[j]);
           if(dist > 2.0 * R)
              continue;
           theta = atan2(p[j].y - p[i].y, p[j].x - p[i].x);
           if(theta < 0)
              theta += 2 * pi;
           phi = acos(dist / (2.0 * R));
           alp[k].v = theta - phi + 2 * pi;
           alp[k].flag = true;
           alp[k + 1].v = theta + phi + 2 * pi;