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class Solution {
 public:
  vector<int> nums;
  Solution(vector<int>& _nums) { nums = _nums; }

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

  vector<int> shuffle() {
    auto a = nums;
    int n = a.size();
    for (int i = 0; i < n; i++) {
      // 将 a[i] 与随机一个 a[i ~ n-1] 交换
      swap(a[i], a[i + rand() % (n - i)]);
    }
    return a;
  }
};

/**
 * 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();
 */