class Solution {
    vector<int> arr, idx;
public:
    Solution(vector<int>& nums) {
        srand(time(NULL)); // generate random
        arr.resize(nums.size());
        idx.resize(nums.size());
        for(int i = 0; i<nums.size();i++)
        {
            arr[i] = nums[i];
            idx[i] = nums[i];
        }

    }

    /** Resets the array to its original configuration and return it. */
    vector<int> reset() {
        for(int i = 0; i<arr.size();i++)
        {
            arr[i] = idx[i];
        }
        return arr;

    }

    /** Returns a random shuffling of the array. */
    vector<int> shuffle() {
        int i,j;
        for(i = arr.size() -1; i>0; i--)
        {
            j = rand() % (i+1); // 0,1,2중으로 계속 나오는 것
            swap(arr[i],arr[j]); // 0,1,2 어레이중의 데이터를 스왑하는 것 랜덤적으로
        }
        return arr;

    }
};

/**
 * 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();
 */