这个helper函数代码少了几行。。我加在这里，我觉得思路很清晰，怎么编译不过呢


        private static List<List<Integer[]>> helper(List<Integer[]> bookSet, int num) {
                
                List<List<Integer[]>> ret = new ArrayList<>();
                List<Integer[]> bookSetCombination=new ArrayList<>();
                
                if(num>bookSet.size()) return ret ;
                
                if(num==1) {
                for (Integer[] book : bookSet)
                        {
                                bookSetCombination.add(book.clone());
                                ret.add(bookSetCombination);
                        }
                return ret;
                }
                
                if (num == bookSet.size()) {
                for (Integer[] book : bookSet)
                        {
                        bookSetCombination.add(book.clone());
                        }
                ret.add(bookSetCombination);
                        return ret;    
            }
                
                if (num < bookSet.size()) {
                
                for (int i=0;i<bookSet.size();i++)
                        {
                        bookSetCombination.add(bookSet.get(i).clone());
            

                        List<Integer[]> tmpBookSet = new ArrayList<>(bookSet);
                        for(Integer[] tmpBook : tmpBookSet) {
                                if(tmpBook.equals(bookSet.get(i))) {
                                        tmpBookSet.remove(tmpBook);      
                                }
                            }
                        
                        ret=helper(tmpBookSet, num-1);
                        for(List<Integer[]> combination :ret) {
                                bookSetCombination.addAll(combination);
                                ret.add(bookSetCombination);
                        }
                        
                        }        
            }
        return ret;
        }


【 在 iStudy 的大作中提到: 】
: 大神，能帮我看这修改一下吗？
: package test;
: import java.util.ArrayList;
: ...................
--
修改:iStudy FROM 58.37.127.*
FROM 58.37.127.*