BOJ 13153 - Formula [C++]

문제

링크

풀이

#include <cmath>
#include <iomanip>
#include <iostream>
#include <vector>
using namespace std;
 
void solve(void) {
  int x1, y1, x2, y2, x3, y3; cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
  double r; cin >> r;
 
  double a = hypot(x1-x2, y1-y2);
  double b = hypot(x2-x3, y2-y3);
  double c = hypot(x3-x1, y3-y1);
 
  double d = 4*a*a*b*b;
  double e = a*a+b*b-c*c;
 
  cout << fixed << setprecision(4) << (sqrt(d-e*e)/(2*(a+b+c))-r)/r*100;
}
 
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
 
  solve();
  return 0;
}