47. 全排列 II

class Solution {
public:
    vectorint>>ans;
    vector<int>path;
    setint> >st;
    void dfs(vector<int>& nums,vector<bool>&used ){
        if(path.size()==nums.size()){
            if(!st.count(path)){
                ans.push_back(path);
                st.insert(path);
            }
        }
        for(int i=0;isize();i++){
            if(used[i]==true)continue;
            path.push_back(nums[i]);
            used[i]=true;
            dfs(nums,used);
            path.pop_back();
            used[i]=false;
        }
    }
    vectorint>> permuteUnique(vector<int>& nums) {
        vector<bool>used(nums.size(),false);
        dfs(nums,used);
        return ans;
    }
};