排列型枚举

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Test {

    static int nn;
    static int[] order;
    static boolean[] vis;
    public static void main(String[] args) throws IOException {
        //通过递归实现排列型枚举
        BufferedReader cin=new BufferedReader(new InputStreamReader(System.in));
        int n=Integer.parseInt(cin.readLine());
        nn=n;
        order=new int[n+1];
        vis=new boolean[n+1];
        dfs(1);
    }
    public static void dfs(int cur){
        if (cur == nn + 1) {
            for(int i=1;i<=nn;i++){
                System.out.print(order[i]+" ");
            }
            System.out.println();
        }
        for(int i=1;i<=nn;i++){
            if(vis[i])continue;
            order[cur]=i;
            vis[i]=true;
            dfs(cur+1);
            order[cur]=0;
            vis[i]=false;
        }
    }
}