java資料結構-約瑟夫環

這個專題記錄自己學習資料結構的過程，也希望能給自學的小夥伴一點幫助。

class Josephu{
    private Boy first =null;
    //增加
    public void addBoy(int num){
        if(num<1){
            System.out.println("輸入資料錯誤");

        }
        Boy temp=null;
        for(int i =1;i<=num;i++){
            Boy boy=new Boy(i);
            if(i==1){
                first=boy;
                temp=first;
                boy.setNext(first);
            }else {
                temp.setNext(boy);
                temp=temp.getNext();
                boy.setNext(first);
            }

        }
    }

    //周遊
    public void list(){
        if(first==null){
            System.out.println("環内無資料");
            return;
        }
        Boy temp=first;
        if(first.getNext()==first){
            System.out.println(temp.toString());
            return;
        }
        while (temp.getNext()!=first){
            System.out.println(temp.toString());
            temp=temp.getNext();
        }
        System.out.println(temp.toString());
    }
    //計數
    public int sort(){
        if(first==null){

            return 0;
        }
        Boy temp=first;
        if(first.getNext()==first){
            System.out.println(temp.toString());
            return 1;
        }
        int i =0;
        while (temp.getNext()!=first){
            i++;
            temp=temp.getNext();
        }
        i++;
        return i;
    }
    //環問題
    public void countBoy(int start,int num){
        int i=this.sort();
        if(start<0||start>i){
            System.out.println("輸入資料有錯誤");
            return;
        }
        if(first.getNext()==first){
            System.out.println(first.toString());
        }
        Boy helper=first;
        while (helper.getNext()!=first){
            helper=helper.getNext();
        }
        for(int j=1;j<start;j++){
            first=first.getNext();
        }
        while(true){
            if(first==helper){
                break;
            }
            for(int j=0;j<num-1;j++){
                first=first.getNext();
                helper=helper.getNext();
            }
            System.out.println(first.toString());
            helper.setNext(first.getNext());
            first=first.getNext();
        }
        System.out.println(first);
    }
}
class Boy {
    private int id ;
    private Boy next;

    @Override
    public String toString() {
        return "Boy{" +
                "id=" + id +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public Boy getNext() {
        return next;
    }