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  1. #include <iostream>
  2. #include <random>
  3. #include <cmath>
  4. #include <limits>
  5. #include <ctime>
  6.  
  7. const std::string currentDateTime() {
  8.     time_t now = time(0);
  9.     struct tm tstruct;
  10.     char buf[80];
  11.     tstruct = *localtime(&now);
  12.     strftime(buf, sizeof(buf), "%Y-%m-%d.%X", &tstruct);
  13.  
  14.     return buf;
  15. }
  16.  
  17. int main()
  18. {
  19.     typedef std::numeric_limits< double > dbl;
  20.  
  21.     std::default_random_engine generator;
  22.     std::normal_distribution<double> distribution(0.0, 1.0);
  23.  
  24.     std::cout.precision(dbl::digits10);
  25.  
  26.     const long long N=1390737600000;
  27.     long long i, in;
  28.  
  29.     double x, y, xz1, yz1, diff;
  30.     xz1 = 0.0;
  31.     yz1 = 0.0;
  32.     diff = 0.0;
  33.  
  34.     x = distribution(generator);
  35.     y = 0.5*yz1 + x - 0.5*xz1;
  36.     diff = std::abs(x-y);
  37.  
  38.     in = 1L;
  39.     for (i=0; i<N; i++){
  40.         x = distribution(generator);
  41.         y = 0.5*yz1 + x - 0.5*xz1;
  42.         diff = diff > std::abs(x-y) ? diff : std::abs(x-y);
  43.         xz1 = x;
  44.         yz1 = y;
  45.  
  46.         if (i == in) {
  47.             std::cout << "[" << currentDateTime() << "] -- " << std::scientific << diff << "  [" << in << "] " << std::endl;
  48.             in *= 10;
  49.         }
  50.     }
  51.  
  52.     std::cout.precision(dbl::digits10);
  53.     std::cout << "Maximum difference is: " << std::scientific << diff << std::endl;
  54.  
  55.     return 0;
  56. }
  57.  
  58. /* Output:
  59.  
  60. [2015-02-25.15:00:56] -- 0.000000000000000e+00  [1] 
  61. [2015-02-25.15:00:56] -- 1.387778780781446e-17  [10] 
  62. [2015-02-25.15:00:56] -- 4.440892098500626e-16  [100] 
  63. [2015-02-25.15:00:56] -- 4.440892098500626e-16  [1000] 
  64. [2015-02-25.15:00:56] -- 4.440892098500626e-16  [10000] 
  65. [2015-02-25.15:00:56] -- 4.440892098500626e-16  [100000] 
  66. [2015-02-25.15:00:56] -- 8.881784197001252e-16  [1000000] 
  67. [2015-02-25.15:00:58] -- 8.881784197001252e-16  [10000000] 
  68. [2015-02-25.15:01:18] -- 8.881784197001252e-16  [100000000] 
  69. [2015-02-25.15:04:36] -- 8.881784197001252e-16  [1000000000] 
  70. [2015-02-25.15:37:35] -- 8.881784197001252e-16  [10000000000] 
  71. [2015-02-25.21:13:03] -- 8.881784197001252e-16  [100000000000] 
  72. [2015-02-28.05:09:45] -- 8.881784197001252e-16  [1000000000000] 
  73. Maximum difference is: 8.881784197001252e-16
  74.  
  75. */
  76.  
Time limit exceeded #stdin #stdout 5s 3232KB
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stdin
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Standard input is empty
stdout
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[2015-03-02.06:31:10] -- 0.000000000000000e+00  [1] 
[2015-03-02.06:31:10] -- 2.032879073410321e-20  [10] 
[2015-03-02.06:31:10] -- 2.710505431213761e-20  [100] 
[2015-03-02.06:31:10] -- 1.084202172485504e-19  [1000] 
[2015-03-02.06:31:10] -- 1.110223024625157e-16  [10000] 
[2015-03-02.06:31:10] -- 1.110223024625157e-16  [100000] 
[2015-03-02.06:31:10] -- 1.110765125711399e-16  [1000000] 
[2015-03-02.06:31:11] -- 2.220446049250313e-16  [10000000]
https://ideone.com/p46LCA
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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