Shuffle a set of numbers without duplicates.

Example:

// Init an array with set 1, 2, and 3.int[] nums = {1,2,3};Solution solution = new Solution(nums);// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.solution.shuffle();// Resets the array back to its original configuration [1,2,3].solution.reset();// Returns the random shuffling of array [1,2,3].solution.shuffle();

class Solution {public:    Solution(vector
     
       nums) {        srand(time(NULL));        _nums=nums;    }        /** Resets the array to its original configuration and return it. */    vector
      
        reset() {        return _nums;    }        /** Returns a random shuffling of the array. */    vector
       
         shuffle() {        vector
        
         shuffle(_nums);        for(int i=_nums.size()-1;i>0;i--){            int pos=rand()%(i+1);            swap(shuffle[i],shuffle[pos]);        }        return shuffle;    }private:    vector
         
          _nums;};/** * Your Solution object will be instantiated and called as such: * Solution obj = new Solution(nums); * vector
          
            param_1 = obj.reset(); * vector
           
             param_2 = obj.shuffle(); */