Solution.cpp

class Solution {
public:
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int n = nums.size();
        vector<vector<int>> ans;
        vector<int> t(n);
        vector<bool> vis(n);
        function<void(int)> dfs = [&](int i) {
            if (i == n) {
                ans.emplace_back(t);
                return;
            }
            for (int j = 0; j < n; ++j) {
                if (vis[j] || (j && nums[j] == nums[j - 1] && !vis[j - 1])) {
                    continue;
                }
                t[i] = nums[j];
                vis[j] = true;
                dfs(i + 1);
                vis[j] = false;
            }
        };
        dfs(0);
        return ans;
    }
};