class Solution { public: vector<vector<int> > permute(vector<int> &num) { vector<vector<int>> res; vector<int> path; vector<bool> used(num.size(), false); dfs(num, res, path, used); return res; } void dfs(vector<int>& num, vector<vector<int>>& res, vector<int> path, vector<bool>& used){ if(path.size() == num.size()){ res.push_back(path); return; } for(int i=0; i<num.size(); i++){ if(used[i]==true) continue; used[i] = true; path.push_back(num[i]); dfs(num, res, path, used); path.pop_back(); used[i] = false; } } };
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