题解 | #有重复项数字的全排列#

class Solution {
private:
    vector<vector<int>> res;
    vector<int> path;
public:
    vector<vector<int> > permuteUnique(vector<int> &num) {
        sort(num.begin(), num.end());
        
        int n = num.size();
        vector<int> vis(n, 0);
        
        dfs(num, vis);
        return res;
    }
    
    void dfs(vector<int>& num, vector<int>& vis){
        if(path.size() == num.size()){
            res.push_back(path);
            return;
        }
        
        for(int i=0; i<num.size(); i++){
            if(vis[i] == 1){
                continue;
            }
            if(i>0 && num[i] == num[i-1] && vis[i-1] == 0){
                continue;
            }
            path.push_back(num[i]);
            vis[i] = 1;
            dfs(num, vis);
            vis[i] = 0;
            path.pop_back();
        }
        
    }
};