偶像生写真和CD内封抽包概率近似计算

ProbabilitySimulation.cpp

#include <algorithm>
#include <array>
#include <functional>
#include <iostream>
#include <random>

using namespace std;

int main()
{
    const int pose = 3; // 3
    const int member = 12;
    const int photo = 5; // 5
    const int package = 10;

    const int times = 100 * 10000;
    int set = 0;

    random_device seeder;
    uniform_int_distribution<int> distribution{1, member * pose};
    array<int, package * photo> values{};

    for (int i = 0; i < times; ++i)
    {
        const auto seed{seeder.entropy() ? seeder() : time(nullptr)};
        mt19937 engine{static_cast<mt19937::result_type>(seed)};
        auto generator{bind(distribution, engine)};
        ranges::generate(values, generator);

        if (ranges::any_of(values,
                           [](int v)
                           {
                               return v == 1;
                           }))
        {
            if (ranges::any_of(values,
                               [](int v)
                               {
                                   return v == 2;
                               }))
            {
                if (ranges::any_of(values,
                                   [](int v)
                                   {
                                       return v == 3;
                                   }))
                {
                    ++set;
                }
            }
        }

        /*
        if (ranges::any_of(values,
                           [](int v)
                           {
                               return v == 1;
                           }))
        {
            ++set;
        }
        */

        /*
        for (auto v : values)
        {
            cout << v << "  ";
        }
        cout << endl;
        */
    }

    cout << set << endl;
    cout << (double)set / (double)times << endl;

    return 0;
}