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  1. #include <vector>
  2. #include <string>
  3. #include <iostream>
  4. #include <iomanip>
  5. #include <chrono>
  6. #include <random>
  7.  
  8. using namespace std;
  9.  
  10. class muTimer
  11. {
  12.     using Clock = std::chrono::high_resolution_clock;
  13.     bool active = false;
  14.     Clock::duration   duration_;
  15.     Clock::time_point start_ = Clock::now(), stop_ = Clock::now();
  16.  
  17.     muTimer(const muTimer&)             = delete;
  18.     muTimer& operator=(const muTimer&)  = delete;
  19. public:
  20.     using ns       = std::chrono::nanoseconds;
  21.     using mks      = std::chrono::microseconds;
  22.     using ms       = std::chrono::milliseconds;
  23.     muTimer() { reset(); start(); }
  24.     ~muTimer() = default;
  25.     muTimer& reset()
  26.     {
  27.         duration_ = std::chrono::nanoseconds(0);
  28.         active    = false;
  29.         return *this;
  30.     }
  31.     muTimer& start()
  32.     {
  33.         if (!active)
  34.         {
  35.             start_ = Clock::now();
  36.             active = true;
  37.         }
  38.         return *this;
  39.     }
  40.     muTimer& stop()
  41.     {
  42.         if (active)
  43.         {
  44.             stop_      = Clock::now();
  45.             duration_ += stop_ - start_;
  46.             active     = false;
  47.         }
  48.         return *this;
  49.     }
  50.     template<typename T = mks>
  51.         unsigned long long duration()
  52.     {
  53.         return static_cast<unsigned long long>
  54.             (std::chrono::duration_cast<T>(stop_-start_).count());
  55.     }
  56. };
  57.  
  58.  
  59. int day(const char * nm)
  60. {
  61.     long long x = nm[0]+nm[1]+nm[2]-300;
  62.     return (((((101047ll*x+694384ll)*x-19207693ll)*x-61935874ll)*x
  63.              +1060034136ll)*x-1218412800)*(2+x)/2058376320+1;
  64. }
  65.  
  66. int DAY(const char * str)
  67. {
  68.     if((str[0] =='M') && (str[1] == 'o') && (str[2] == 'n')) return 1;
  69.     if((str[0] =='T') && (str[1] == 'u') && (str[2] == 'e')) return 2;
  70.     if((str[0] =='W') && (str[1] == 'e') && (str[2] == 'd')) return 3;
  71.     if((str[0] =='T') && (str[1] == 'h') && (str[2] == 'u')) return 4;
  72.     if((str[0] =='F') && (str[1] == 'r') && (str[2] == 'i')) return 5;
  73.     if((str[0] =='S') && (str[1] == 'a') && (str[2] == 't')) return 6;
  74.     if((str[0] =='S') && (str[1] == 'u') && (str[2] == 'n')) return 7;
  75.     return 0;
  76. }
  77.  
  78. int DAY2(const char * str)
  79. {
  80. 	const int days[23] = {3, 5, 0, 0, 0, 0, 0, 0, 6, 0, 1,
  81. 		0, 0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 7};
  82.  
  83. 	int index = str[0] + str[1] + str[2] - 288;
  84. 	return days[index];
  85. }
  86.  
  87. int main()
  88. {
  89.  
  90.     char M[7][4] = { "Mon","Tue","Wed","Thu","Fri","Sat","Sun" };
  91.  
  92.     const std::size_t vect_size = 20000000;
  93.     std::vector<char> rand_vect(vect_size);
  94.     std::mt19937 gen(0);
  95.     std::uniform_int_distribution<> distrib(0,6);
  96.     for (int i = 0; i < vect_size; ++i)
  97.     	rand_vect[i] = distrib(gen);
  98.  
  99.     {
  100.         int sum = 0;
  101.         muTimer mt;
  102.         for(int i = 0; i < vect_size; ++i)
  103.         {
  104.             sum += day(M[rand_vect[i]]);
  105.         }
  106.         mt.stop();
  107.         cout << "day:  " << sum << " for " << mt.duration<>() << " mks\n";
  108.     }
  109.     {
  110.         int sum = 0;
  111.         muTimer mt;
  112.         for(int i = 0; i < vect_size; ++i)
  113.         {
  114.             sum += DAY(M[rand_vect[i]]);
  115.         }
  116.         mt.stop();
  117.         cout << "DAY:  " << sum << " for " << mt.duration<>() << " mks\n";
  118.     }
  119.     {
  120.         int sum = 0;
  121.         muTimer mt;
  122.         for(int i = 0; i < vect_size; ++i)
  123.         {
  124.             sum += DAY2(M[rand_vect[i]]);
  125.         }
  126.         mt.stop();
  127.         cout << "DAY2: " <<sum << " for " << mt.duration<>() << " mks\n";
  128.     }
  129.  
  130. }
  131.  
Success #stdin #stdout 0.88s 22548KB
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stdin
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Standard input is empty
stdout
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day:  80000618 for 118038 mks
DAY:  80000618 for 193692 mks
DAY2: 80000618 for 75739 mks
https://ideone.com/vfeV6O
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
public

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