Solution(vector<int> nums) : _nums(nums), _solution(nums) {

srand(time(NULL));

}

/** Resets the array to its original configuration and return it. */

vector<int> reset() {

return _solution = _nums;

}

/** Returns a random shuffling of the array. */

vector<int> shuffle() {

//Fisher Yates

//https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle

int i = _solution.size();

while ( --i > 0 ) {

int j = rand() % (i+1);

swap(_solution[i], _solution[j]);

}

return _solution;

}

vector<int> _nums, _solution;