Submission #3594603

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Source Code Expand

#include <iostream>
#include <fstream>
#include <cmath>  
#include <cstdlib>
#include <ctime>
#include <algorithm>
#include <numeric>
#include <functional>
#include <string> 
#include <vector>
#include <bitset>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>

using namespace std;
using ll = long long;

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;

#define REP(i,n) for(int i = 0; i < int(n); i++)
#define FOR(i, m, n) for(int i = int(m);i < int(n);i++)
#define ALL(obj) (obj).begin(),(obj).end()

const ll MOD = (ll)1e9 + 7;
const ll HINF = (ll)1e18;
const ll LINF = (ll)1e9;
const long double PI = 3.1415926535897932384626433;

vector<int> dy = { 0,0,1,-1 };
vector<int> dx = { 1,-1,0,0 };

template<class T> void corner(bool flg, T hoge) {
	if (flg) {
		cout << hoge << endl;
		exit(0);
	}
	else return;
}

template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {
	o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;
}

template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {
	o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;
}

template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {
	o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;
}

template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {
	o << "{" << obj.first << ", " << obj.second << "}"; return o;
}

template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {
	o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;
}

void print(void) {
	cout << endl;
}

template <class Head> void print(Head&& head) {
	cout << head;
	print();
}

template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {
	cout << head << " ";
	print(forward<Tail>(tail)...);
}

void YN(bool flg) {
	cout << ((flg) ? "YES" : "NO") << endl;
}

void Yn(bool flg) {
	cout << ((flg) ? "Yes" : "No") << endl;
}

void yn(bool flg) {
	cout << ((flg) ? "yes" : "no") << endl;
}


int main() {
	double R; cin >> R;
	int N, M; cin >> N >> M;
	V<double> L(N + 1, 0.);
	for (int i=0; i < N; ++i) {
		double x = 2 * R*i / N;
		x = abs(x - R);
		L[i] = 2*sqrt(R*R-x*x);
	}
	double ans = 0.;
	FOR(i,1,N+M){
		ans += max(L[(i<=N)?i:0], L[(0<=i-M)?(i - M):0]);
	}
	printf("%.10f", ans);
	
	return 0;
}

Submission Info

Judge Result