class Solution {
public:
    Solution(vector<int>& nums)
      : m_original(nums) {}

    vector<int> reset() {
        return m_original;
    }

    vector<int> shuffle() {
        std::vector<int> shuffled = m_original;
        for (size_t i = 0; i < shuffled.size(); ++i) {
            const size_t j = random() % shuffled.size();
            std::swap(shuffled[i], shuffled[j]);
        }
        return shuffled;
    }

private:
    size_t random() {
        uint64_t x = m_random;

        // xorshift64
        x ^= x << 13;
        x ^= x >> 7;
        x ^= x << 17;

        m_random = x;
        return x;
    }

    std::vector<int> m_original;
    std::uint64_t    m_random = 16240738485554559101;
};

/**
 * Your Solution object will be instantiated and called as such:
 * Solution* obj = new Solution(nums);
 * vector<int> param_1 = obj->reset();
 * vector<int> param_2 = obj->shuffle();
 */