全排列(計蒜客)

代碼如下:

package _計蒜客._深搜習題;

import java.util.Scanner;

public class _全排列 {
    static int n;
    static boolean[] vis=new boolean[20];

    static void dfs(int cnt,int num){
        if(cnt==n){
            System.out.println(num);
            return;
        }

        for (int i = 1; i <=n ; i++) {//對每個數字進行嘗試
            if(!vis[i]){
                vis[i]=true;
                dfs(cnt+1,num*10+i);
                vis[i]=false;
            }
        }
    }
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        n=sc.nextInt();
        int ans=1;
        for (int i = 1; i <=n ; i++) {//ans為n!
            ans*=i;
        }
        System.out.println(ans);
        dfs(0,0);
    }
}