47

class Solution {
public:
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        vector<vector<int>> ans;
        sort(nums.begin(), nums.end());
        permute(nums, 0, ans);
        return ans;
    }

    void permute(vector<int> nums, int idx, vector<vector<int>> &ans){
          if(idx == nums.size())
              ans.push_back(nums);

          for(int i=idx; i<nums.size(); i++){
              if(i != idx && nums[idx] == nums[i])
                  continue;
              swap(nums[i], nums[idx]);
              permute(nums, idx+1, ans);
          }
    }
};