import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;public class Test44 {//打印一个字符串全部子序列，要求不出现重复字面值public static List<String> subsNoRepeat(String s) {char[] str = s.toCharArray();String path = "";HashSet<String> set = new HashSet<>();process2(str , 0 , set , path);List<String> ans = new ArrayList<>();for (String cur : set) {ans.add(cur);}return ans;}public static void process2(char[] str , int index , HashSet<String> set , String path) {if(index == str.length) {set.add(path);return;}String no = path;process2(str , index + 1, set, no);String yes = path + String.valueOf(str[index]);process2(str , index + 1 , set, yes);}
}
