全排列Java

package day0207;

import java.util.Scanner;

public class 全排列 {

	static int [] box = null;
	static int [] book = null;
	static int n;
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner scan = new Scanner(System.in);
		n = scan.nextInt();
		box = new int[n+1];
		book = new int[n+1];
		dfs(1);
		
	}
	
	public static void dfs(int step) {
		if(step==n+1) {
			for (int i = 1; i < box.length; i++) {
				System.out.print(box[i]+" ");
			}
			System.out.println();
			return ;
		}
		
		for (int i = 1; i <= n; i++) {
			if(book[i]==0) {//判定i是否已经用过
				box[step] = i;
				book[i] = 1;//i已经用过
				dfs(step+1);
				box[step] = 0;
				book[i] = 0;//i没有用过
			}
		}
	}

}