这两天终于记得写；了
用python用习惯了lambda，把java的函数式编程也搞起~
这题好像也不用状态压缩，不过写都写了嘛
想了下，不用状态压缩的原因是序列是顺序的，是有限的

import java.util.*;
import java.util.stream.*;

public class Main{
    private Scanner jin = new Scanner(System.in);
    private List<Integer> buffer = new ArrayList<>();


    void run(){
        int n = jin.nextInt();
        dfs(n, 0, 0);
    }

    void dfs(int n, int status, int x){
        if (status == (1 << n) - 1){
            String res = String.join(" ", buffer.stream().map(y->String.valueOf(y+1)).collect(Collectors.toList()));
            System.out.println(res);
        } else {
            dfs(n, status | (1 << x), x+1);

            buffer.add(x);
            dfs(n, status | (1 << x), x + 1);
            buffer.remove(buffer.size() - 1 );
        }
    }
    public static void main(String[] args){new Main().run();}
}