Submission #7663738

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <utility>
#include <tuple>
#include <algorithm>
#include <numeric>
#include <cstdio>
#include <cmath>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

int main() {
  double R;
  int N, M;
  cin >> R >> N >> M;
  double ans = 0;
  
  auto cal_x = [=](int i) {
    if (i <= 0 || i >= N)
      return 0.0;
    double y = R*2/N*i-R;
    return sqrt(abs(R*R-y*y));
  };
  
  for (int i=1; i<N+M; i++)
    ans += max(cal_x(i)*2, cal_x(i-M)*2);
  cout << fixed << setprecision(6) << ans << endl;
  return 0;
}

Submission Info

Judge Result