shuffle-an-array.cc

// Shuffle an Array
class Solution {
  vector<int> a;
public:
  Solution(vector<int> nums) : a(nums) {}

  /** Resets the array to its original configuration and return it. */
  vector<int> reset() { return a; }

  /** Returns a random shuffling of the array. */
  vector<int> shuffle() {
    auto r = a;
    for (size_t i = 1; i < r.size(); i++)
      swap(r[rand()%(i+1)], r[i]);
    return r;
  }
};

/**
 * 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();
 */