B - Inscribed Bicycle

Quiz

https://atcoder.jp/contests/cf16-exhibition-final-open/tasks/cf16_exhibition_final_b

Submission

https://atcoder.jp/contests/cf16-exhibition-final-open/submissions/7185546

成果物のライブラリ

// ヘロンの公式（三角形の面積）
double heron(double a, double b, double c){
  double s = (a+b+c)/2;
  double temp = s * (s-a) * (s-b) * (s-c);
  return sqrt(temp);
}

// 内接円の半径
double incircle_radius(double a, double b, double c){
  double S = heron(a, b, c);
  return 2*S/(a+b+c);
}