Simulate the number of expected number of duplicate nonces in the Bitcoin block chain

duplicates.cpp

#include <algorithm>
#include <iostream>
#include <random>

constexpr uint16_t REPEATS{100};
constexpr uint32_t BLOCK_HEIGHT{674293};
 
uint16_t run(int seed)
{
    std::seed_seq seq{seed};

    std::vector<uint32_t> nonces(BLOCK_HEIGHT);
    seq.generate(nonces.begin(), nonces.end());  // seed_seq.generate() generates a sequence of 32 bit outputs
    std::sort(nonces.begin(), nonces.end());

    uint16_t duplicates{0};
    auto it = nonces.begin();
    while (it != nonces.end()) {
        auto next = it + 1;
        if (next != nonces.end() && *it == *next) ++duplicates;
        it = next;
    }
    return duplicates;
}

int main()
{
    float total{0};
    for (auto i=0; i<REPEATS; ++i) {
        auto result = run(i);
        std::cout << result << std::endl;
        total += result;
    }
    
    std::cout << "Average = " << total / REPEATS << std::endl;

    return 0;
}

Wow. Thanks for the detailed reply!