Leetcode_46. 全排列_47. 全排列 II

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code

class Solution {
public:
    bool vis[100005]={false};
    void dfs(vector<vector<int>>& ans,vector<int>& a,int idx,vector<int>& nums,int n){
        if(idx==n){
            ans.push_back(a);
            return;
        }
        for(int i=0;i<n;i++){
            if(!vis[i]){
                vis[i]=true;
                a.push_back(nums[i]);
                dfs(ans,a,idx+1,nums,n);
                a.pop_back();
                vis[i]=false;
            }
        }
    }
    vector<vector<int>> permute(vector<int>& nums) {
        vector<vector<int>> ans;
        vector<int> a;
        int n=nums.size();
        dfs(ans,a,0,nums,n);
        return ans;
    }
};

class Solution {
public:
    bool vis[100005]={false};
    void dfs(set<vector<int>>& ans,vector<int>& a,int idx,vector<int>& nums,int n){
        if(idx==n){
            ans.insert(a);
            return;
        }
        for(int i=0;i<n;i++){
            if(!vis[i]){
                vis[i]=true;
                a.push_back(nums[i]);
                dfs(ans,a,idx+1,nums,n);
                a.pop_back();
                vis[i]=false;
            }
        }
    }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        set<vector<int>> ans;
        vector<int> a;
        int n=nums.size();
        dfs(ans,a,0,nums,n);
        vector<vector<int>> res;
        for(auto s:ans){
            res.push_back(s);
        }
        return res;
    }
};