单向链表(Java实现)

package com.kk.test;

import java.util.ArrayList;
import java.util.List;

public class Node {

    private int value;

    private Node nextNode;


    public Node() {
    }

    public Node(int value) {
        this.value = value;
    }

    public Node(int value, Node nextNode) {
        this.value = value;
        this.nextNode = nextNode;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public Node getNextNode() {
        return nextNode;
    }

    public void setNextNode(Node nextNode) {
        this.nextNode = nextNode;
    }


    //打印链表
    public void printNode(){
        Node node = this;
        while (true){
            System.out.print(node.value+"->");
            node = node.getNextNode();
            if (node == null){
                System.out.println();
                break;
            }
        }
    }

    //判断是否有环
    public boolean isCycle(){
        List list = new ArrayList<>();
        Node node = this;
        while (true){
            if (list.contains(node)){
                return true;
            }
            list.add(node);
            node = node.getNextNode();
            if (node == null){
                return false;
            }
        }
    }
}

示例

	public static void main(String[] args) {
        Node last = new Node(99);
        Node node = new Node(1, new Node(2, new Node(3, new Node(4, last))));
        //last.setNextNode(node);
        //node.printNode();
        System.out.println(node.isCycle());
    }