Losowanie prezentów

main.cpp

#include <iostream> 
#include <vector>
#include <algorithm>
#include <stdlib.h>

int getRandom(int a, int b) {
    return a + (rand() % (b - a));
}

bool isOk(std::vector<int> const& vec) {
    for (int i = 0; i < vec.size(); ++i) {
        if (i == vec[vec[i]]) {
            return false;
        }
    }
    return true;
}

std::vector<int> permutation(int n) {
    std::vector<int> vec(n);
    while (n--) {
        vec[n] = n;
    }
    
    int forceTimes = n * n - 1;
    while (forceTimes > 0 || !isOk(vec)) {
        int x = getRandom(0, vec.size());
        int y = getRandom(0, vec.size());
        if (x != y) {
            std::swap(vec[x], vec[y]);
            forceTimes--;
        }
    }

    return vec;
}

int main(int argc, char** argv) {
    std::vector<std::string> data;
    std::string line; 
    srand(time(NULL));

    while (std::getline(std::cin, line)) {
        data.push_back(line);
    }

    std::sort(data.begin(), data.end());

    std::vector<int> perm = permutation(data.size());

    for (int i = 0; i < data.size(); ++i) {
        std::string cmd = "printf \"" + data[i] + " \" &&" +
            "echo \"openssl enc -base64 <<< '" + data[perm[i]] + "'\" | bash";
        std::system(cmd.c_str());
    }

    return 0;
}