DFS实现全排列

复习一下DFS实现全排列，具体思想见：https://www.cnblogs.com/chiweiming/p/9279858.html

public class Main{
 
    static int arr[]=new int[6];
    static int book[]=new int[6];
    static int result=0;
 
    static void fun(int N){
        if(N==6){
            result++;
            for(int i=1;i<=5;i++){
                System.out.print(arr[i]+" ");
            }
            System.out.println();
            return;
        }
        for(int i=1;i<=5;i++){    //每个位置都尝试填入1~5
            if(book[i]==0){
                book[i]=1;
                arr[N]=i;
                fun(N+1);
                book[i]=0;
            }
        }
    }
 
    public static void main(String[] args)    {
        fun(1);
        System.out.println(result);
    }
}