单向环形链表和约瑟夫问题

单向环形链表和约瑟夫问题

应用场景

当n=5;m=2,k=1时出队列的顺序：2->4->1->5->3

一个节点也能形成环链

构建思路

构建一个单向的环形链表思路
1.先创建第一个节点,让first指向该节点，并形成环形.
2.后面当我们每创建一个新的节点，就把该节点，加入到已有的环形链表中即可.

public void addNode(int nums){
    if (nums < 1){
        System.out.println("nums的值不正确");
        return;
    }
    //构建辅助指针，帮助创建环形链表
    Node temp = null;
    for (int i = 1; i <= nums; i++) {
        Node node = new Node(i);
        if (i==1){
            first = node;
            first.setNext(first);
            temp = first;
        }else {
            temp.setNext(node);
            node.setNext(first);
            temp = node;
        }
    }
}

遍历环形链表

1.先让一个辅助指针(变量)temp,指向first节点
2.然后通过一个while循环遍 历该环形链表即可temp.next == first结束

//遍历环形链表
public void showNode(){
    if (first == null){
        System.out.println("链表为空");
        return;
    }
    Node temp = first;
    while (true){
        System.out.printf("节点的编号%d\n",temp.getNo());
        if (temp.getNext() == first){
            break;
        }
        temp = temp.getNext();
    }
}

约瑟夫问题代码实现

package Linked;

public class Josephu {
    public static void main(String[] args) {
        CircleSingleLinkedList circleSingleLinkedList = new CircleSingleLinkedList();
        circleSingleLinkedList.addNode(5);
        circleSingleLinkedList.showNode();
        System.out.println("结果");
        circleSingleLinkedList.nextKNode(1,2,5);
    }
}
class Node{
    private int no;
    private Node next;

    public Node(int no) {
        this.no = no;
    }
    public int getNo() {
        return no;
    }
    public void setNo(int no) {
        this.no = no;
    }
    public Node getNext() {
        return next;
    }
    public void setNext(Node next) {
        this.next = next;
    }
}
class CircleSingleLinkedList{
        Node first = new Node(-1);
    //添加节点，构成环形链表
    public void addNode(int nums){
        if (nums < 1){
            System.out.println("nums的值不正确");
            return;
        }
        //构建辅助指针，帮助创建环形链表
        Node temp = null;
        for (int i = 1; i <= nums; i++) {
            Node node = new Node(i);
            if (i==1){
                first = node;
                first.setNext(first);
                temp = first;
            }else {
                temp.setNext(node);
                node.setNext(first);
                temp = node;
            }
        }
    }
    //遍历环形链表
    public void showNode(){
        if (first == null){
            System.out.println("链表为空");
            return;
        }
        Node temp = first;
        while (true){
            System.out.printf("节点的编号%d\n",temp.getNo());
            if (temp.getNext() == first){
                break;
            }
            temp = temp.getNext();
        }
    }
    //删除相应的节点
    //startNo开始的位置，step表示数几下，nums是节点数
    public void nextKNode(int startNo,int step ,int nums){
        if (first == null || startNo < 1 || startNo > nums){
            System.out.println("参数输入有误");
            return;
        }
        Node temp = first;
        //temp指向first的前一个节点
        while (true){
            if (temp.getNext() == first){
                break;
            }
            temp = temp.getNext();
        }
        //先将temp和first移动到相应的位置
        for (int i = 0; i <startNo-1 ; i++) {
            first = first.getNext();
            temp = temp.getNext();
        }
        //
        while (true){
            //只有一个节点
            if (temp == first){
                System.out.printf("删除%d号节点\n",first.getNo());
                break;
            }
            //让temp和first移动step-1次，然后删除节点,first指向的节点就是要删除的节点
            for (int i = 0; i <step-1 ; i++) {
                first = first.getNext();
                temp = temp.getNext();
            }
            System.out.printf("删除%d号节点\n",first.getNo());
            first = first.getNext();
            temp.setNext(first);
        }
    }
}