Java递归实现全排列改进(二)---利用ArrayList实现去重

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

public class Test{

 private static String[] s = new String[]{"a","b","a"};

 private static int l = s.length;

 private static List<String> list = new ArrayList<String>();

 public static void main(String[] args) {

  List<String> source = Arrays.asList(s);

  List<String> target = new ArrayList<String>();

  sort(source,target);

 }

 private static void sort(List<String> source, List<String> target) {

  if(target.size() == l){

   if(!list.contains(target.toString())){

    list.add(target.toString());

    for(int i=0;i<target.size();i++){

     System.out.print(target.get(i));

    }

    System.out.println();

   }

  }

  for(int i=0;i<source.size();i++){

   List<String> targetList = new ArrayList<String>(target);

   targetList.add(source.get(i));

   List<String> resourceList = new ArrayList<String>(source);

   resourceList.remove(i);

   sort(resourceList,targetList);

  }

 }

}