47.全排列 2

class Solution {
public:
    vector<vector<int>> permuteUnique(vector<int>& nums) {
  //     set<vector<int>> va;
       vector<int> trace;
        vector<vector<int>> va1;
        vector<int> visited(nums.size(),0);
       permuteUnique(va1,trace,nums,visited);
      
   
       return va1; 
    }
    void permuteUnique(vector<vector<int>> &va,vector<int> &trace,vector<int> &nums,vector<int> &visited)
    {
        if(nums.size()==trace.size())
        {
            va.push_back(trace);
        }
        for(int i=0;i<nums.size();i++)
        {
            if(visited[i]==1) continue;
            if (i > 0 && nums[i] == nums[i - 1] && visited[i - 1] == 0) continue;
            visited[i]=1;
            trace.push_back(nums[i]);
            permuteUnique(va,trace,nums,visited);
            trace.pop_back();
            visited[i]=0;
        }
    }
};