結果

問題 No.454 逆2乗和
ユーザー koyumeishi
提出日時 2016-12-05 00:42:05
言語 C++14
(gcc 7.2.0)
結果
AC  
実行時間 1981 ms
コード長 3783 Byte
コンパイル時間 6903 ms
使用メモリ 1564 KB

テストケース

テストケース表示
入力 結果 実行時間
使用メモリ
99_system_test1.txt AC 6 ms
1556 KB
gen_case1.txt AC 1953 ms
1560 KB
gen_case2.txt AC 1956 ms
1560 KB
gen_case3.txt AC 1979 ms
1564 KB
gen_case4.txt AC 1959 ms
1560 KB
gen_case5.txt AC 1954 ms
1560 KB
gen_case6.txt AC 4 ms
1556 KB
gen_case7.txt AC 1980 ms
1564 KB
gen_case8.txt AC 1981 ms
1564 KB
gen_case9.txt AC 1957 ms
1564 KB
gen_case10.txt AC 1967 ms
1564 KB
gen_case11.txt AC 1948 ms
1560 KB
gen_case12.txt AC 1946 ms
1564 KB
gen_case13.txt AC 1970 ms
1560 KB
gen_case14.txt AC 1966 ms
1560 KB
gen_case15.txt AC 1974 ms
1564 KB
gen_case16.txt AC 1966 ms
1560 KB
gen_case17.txt AC 1959 ms
1560 KB
gen_case18.txt AC 1957 ms
1564 KB
gen_case19.txt AC 1956 ms
1564 KB
gen_case20.txt AC 1956 ms
1560 KB
sample1.txt AC 5 ms
1552 KB
sample2.txt AC 1953 ms
1564 KB
sample3.txt AC 4 ms
1560 KB
system_test1.txt AC 4 ms
1560 KB
system_test2.txt AC 4 ms
1552 KB
system_test3.txt AC 4 ms
1556 KB
system_test4.txt AC 4 ms
1556 KB
system_test5.txt AC 4 ms
1556 KB
system_test6.txt AC 4 ms
1556 KB
system_test7.txt AC 4 ms
1560 KB
system_test8.txt AC 4 ms
1556 KB
system_test9.txt AC 4 ms
1560 KB
system_test10.txt AC 4 ms
1560 KB
テストケース一括ダウンロード

ソースコード

diff #
#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;

int main(){
  double n;
  cin >> n;

  using real = long double;

  real pi = acos((real)-1.0);
  real ans = pi*pi/6.0;

  if(n == floor(n)){
    for(long long i=1; i<=n; i+=1){
      ans -= 1.0/(i*i);
    }

    printf("%.16f\n", (double)ans);
    return 0;
  }

  real diff = 100;
  real t=n+1;
  ans = 0;
  while(diff>1e-17){
    diff = 1.0/(t*t);
    ans += diff;
    t+=1.0;
  }
  printf("%.16f\n", (double)ans + 3e-9);

  return 0;
}
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