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  1. #include <cstdio>
  2. #include <vector>
  3. #include <cmath>
  4.  
  5. struct Point {
  6.     double x, y;
  7.  
  8.     Point (double x = 0, double y = 0) : x(x), y(y) { }
  9.  
  10.     static Point read() {
  11.         double x, y;
  12.         scanf("%lf %lf", &x, &y);
  13.         return Point(x, y);
  14.     }
  15.  
  16.     bool in_circle(const double r) const {
  17.         return x*x+y*y < r*r;
  18.     }
  19. };
  20.  
  21. Point operator -(const Point & left, const Point & right) {
  22.     return Point(left.x-right.x, left.y-right.y);
  23. }
  24.  
  25. Point operator +(const Point & left, const Point & right) {
  26.     return Point(left.x+right.x, left.y + right.y);
  27. }
  28.  
  29. Point operator *(const Point & left, const double right) {
  30.     return Point(left.x * right, left.y * right);
  31. }
  32.  
  33. Point operator *(const double left, const Point & right) {
  34.     return right * left;
  35. }
  36.  
  37. double det(const Point & left, const Point & right) {
  38.     return left.x * right.y - left.y * right.x;
  39. }
  40.  
  41. struct Line {
  42.     Point A, B;
  43.  
  44.     Line (const Point & A = Point(), const Point & B = Point()) : A(A), B(B) { }
  45.  
  46.     static Line read() {
  47.         return Line(Point::read(), Point::read());
  48.     }
  49.  
  50.     Point intersect(const Line & other) const {
  51.         return other.A + (other.B-other.A) * (det(other.A - A, B-A) / det(B-A, other.B-other.A));
  52.     }
  53. };
  54.  
  55. int main() {
  56.     //freopen("input.txt", "rt", stdin);
  57.  
  58.     double r;
  59.     int k;
  60.     scanf("%lf %d", &r, &k);
  61.  
  62.     int count = 1+k;
  63.     std::vector<Line> v(k);
  64.     for (int i = 0; i < (int) v.size(); ++i) {
  65.         v[i] = Line::read();
  66.         for (int j = 0; j < i; ++j) {
  67.             count += v[i].intersect(v[j]).in_circle(r);
  68.         }
  69.     }
  70.  
  71.     printf("%d", count);
  72.  
  73.     return 0;   
  74. }
Success #stdin #stdout 0s 4460KB
comments (?)
stdin
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99.999999 2
-99.999999 0 99.999998 0.014142
-99.999998 0 99.999998 0.014142
stdout
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4
https://ideone.com/dpRiL1
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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