Submission #7973444

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define INF 1000000010
#define EPS 1e-9
#define fst first
#define scd second

#define debug(x) cout<<x<<endl;
#define repi(i,x,n) for(int i=x;i<n;i++)
#define rep(i,n) repi(i,0,n)
#define lp(i,n) repi(i,0,n)
#define repn(i,n) for(int i=n;i>=0;i--)
#define int long long
#define endl "\n"

 double r,n,m;

double calc(int x){
  if(x<=0 || x>=n) return 0;
  double k=fabs(r-2*r/n*x);
  return sqrt(r*r-k*k)*2;
}

signed main(){
  cin.tie(0);	
  ios::sync_with_stdio(false);
  cout<<fixed<<setprecision(12);
 
  cin>>r>>n>>m;
  double ans=0;
  double one=(r*2)/n;
  rep(i,n+m){
    ans+=max(calc(i),calc(i-m));
  }
  cout<<ans<<endl;

  return 0;
}

Submission Info

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