class Solution {
public:
    vector<int> path;
    vector<vector<int>> result;

    void dfs(vector<int>& nums, vector<bool>& used) {
        if (path.size() == nums.size()) {
            result.push_back(path);
            return ;
        }
        for (int i = 0; i < nums.size(); i++) {
            if (i > 0 && nums[i] == nums[i-1] && used[i-1] == false) continue;
            if (!used[i]) {
                used[i] = true;
                path.push_back(nums[i]);
                dfs(nums, used);
                path.pop_back();
                used[i] = false;
            }
        }
    }

    vector<vector<int>> permutation(vector<int>& nums) {
        path.clear();
        result.clear();
        vector<bool> used(nums.size(), false);
        sort(nums.begin(), nums.end());
        dfs(nums, used);
        return result;
    }
};