Java递归实现全排列改进(一)---利用HashSet实现去重

import java.util.Arrays;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

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

private static int l = s.length;

private static Set<String> set = new HashSet<String>();

public static void main(String[] args) {

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

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

sort(source,target);

Iterator<String> it = set.iterator();

while(it.hasNext()){

System.out.println(it.next());

}

if(target.size() == l){

set.add(target.toString().replaceAll(",", "").replace("[", "").replace("]", "").replace(" ", ""));

}

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);

}

}