1、2、2、3、4、5这六个数字,用java写一个main函数，打印出所有不同的排列,如：512234等.要求："4"不能在第三位，"3"与"5不能相连

import java.util.Iterator;
import java.util.TreeSet;

/**
 * time 2011/03/18
 * @author liuxingyu
 *
 */
public class Travel_Graph {

	private String[] b = new String[]{"1","2","2","3","4","5"};
	private int n = b.length;
	private boolean[] visited = new boolean[n];
	private int[][] a = new int[n][n];
	private String result ="";
	private TreeSet<String>  TreeSet = new  TreeSet<String>();
	
	private void start(){
		for(int i = 0 ;i<n;i++){
			for(int j=0; j<n ;j++){
				if(i==j){
					a[i][j]=0;
				}else{
					a[i][j]=1;
				}
			}
		}
		a[3][5]=0;
		a[5][3]=0;
		for(int i =0;i<n;i++){
			this.depthFirstSearch(i);
		}
		Iterator<String> it = TreeSet.iterator();
		while(it.hasNext()){
			String string = (String)it.next();
			if(string.indexOf("4")!=2){
				System.out.println(string);
			}
		}
		
	}
	
	private void depthFirstSearch(int startIndex) {
		visited[startIndex]=true;
		result = result+b[startIndex];
		if(result.length()==n){
			TreeSet.add(result);
		}
		for(int j=0;j<n;j++){
			if(a[startIndex][j]==1&& visited[j]==false){
				depthFirstSearch(j);
			}else{
				continue;
			}
		}
		result = result.substring(0,result.length()-1);
		visited[startIndex]= false;
	}

	public static void main(String[] args) {
		new Travel_Graph().start();
	}

}