BOJ 25084 - Infinity Area [C++]

문제

링크

풀이

#include <cmath>
#include <iomanip>
#include <iostream>
using namespace std;
 
inline double area(int r) {
  return acos(-1) * r * r;
}
 
void solve(int idx) {
  int r, a, b; cin >> r >> a >> b;
 
  double ans = 0;
  while (r >= 1) {
    ans += area(r);
    r *= a;
    ans += area(r);
    r /= b;
  }
  cout << "Case #" << idx << ": " << fixed << setprecision(7) << ans << "\n";
}
 
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
 
  int t; cin >> t;
  for (int i=1; i<=t; i++) solve(i);
  return 0;
}