Java实现单链表的合并(保证数据的有序性)

一、思路

1.比较两个链表的大小
2.将小链表插入到大链表中
3.使用插入保证链表数据的有序性

二、核心代码

  /**
     * 合并两个链表，并且按照有序合并
     * @param singleLinkedList1 链表1
     * @param singleLinkedList2 链表2
     */
    public static void mergeLinkedList2(SingleLinkedList singleLinkedList1, SingleLinkedList singleLinkedList2) {
        int num1 = getLength(singleLinkedList1.getNode());
        int num2 = getLength(singleLinkedList2.getNode());
        if (singleLinkedList1.getNode().next == null || singleLinkedList2.getNode().next == null) {
            return;
        }
        if (num1 >= num2) {
            Node cur = singleLinkedList2.getNode().next;
            Node cur2 = null;
            while (cur != null) {
                cur2 = cur.next;
                singleLinkedList1.insert(cur);
                cur = cur2;
            }
        } else {
            Node temp = singleLinkedList1.getNode().next;
            Node temp2 = null;
            while (temp != null) {
                temp2 = temp.next;
                singleLinkedList2.insert(singleLinkedList1.getNode());
                temp = temp2;
            }
        }
    }

三、全代码

package com.company;

import java.util.Stack;

/**
 * @author:抱着鱼睡觉的喵喵
 * @date:2021/2/4
 * @description:
 */
public class LinkedListDemo {
    public static void main(String[] args) {
        Node node4 = new Node(4, 96, "Ronin");
        Node node1 = new Node(2, 100, "lisi");
        Node node2 = new Node(1, 99, "张三");
        Node node3 = new Node(3, 63, "zsh");
        Node node5 = new Node(5, 65, "zms");

        SingleLinkedList singleLinkedList = new SingleLinkedList();
        SingleLinkedList singleLinkedList2 = new SingleLinkedList();

        singleLinkedList.insert(node4);
        singleLinkedList.insert(node1);
        singleLinkedList.insert(node2);
        singleLinkedList2.insert(node3);
        singleLinkedList2.insert(node5);
        mergeLinkedList2(singleLinkedList,singleLinkedList2);
        int num1 = getLength(singleLinkedList.getNode());
        int num2 = getLength(singleLinkedList2.getNode());
        if (num1 >= num2) {
            singleLinkedList.list();
        } else {
            singleLinkedList2.list();
        }

    }

    //计算链表长度
    public static int getLength(Node node) {
        if (node.next == null) {
            return 0;
        }
        int length = 0;
        Node cur = node.next;
        while (cur != null) {
            length++;
            cur = cur.next;
        }
        return length;
    }

    /**
     * 合并两个链表，并且按照有序合并
     * @param singleLinkedList1 链表1
     * @param singleLinkedList2 链表2
     */
    public static void mergeLinkedList2(SingleLinkedList singleLinkedList1, SingleLinkedList singleLinkedList2) {
        int num1 = getLength(singleLinkedList1.getNode());
        int num2 = getLength(singleLinkedList2.getNode());
        if (singleLinkedList1.getNode().next == null || singleLinkedList2.getNode().next == null) {
            return;
        }
        if (num1 >= num2) {
            Node cur = singleLinkedList2.getNode().next;
            Node cur2 = null;
            while (cur != null) {
                cur2 = cur.next;
                singleLinkedList1.insert(cur);
                cur = cur2;
            }
        } else {
            Node temp = singleLinkedList1.getNode().next;
            Node temp2 = null;
            while (temp != null) {
                temp2 = temp.next;
                singleLinkedList2.insert(singleLinkedList1.getNode());
                temp = temp2;
            }
        }
    }
}

//节点类
class Node {
    public Node next;
    public int sno;
    public int score;
    public String data;

    public Node() {
    }

    public Node(int Sno, int NScore, String Data) {
        this.sno = Sno;
        this.score = NScore;
        this.data = Data;
    }

    @Override
    public String toString() {
        return "Node{" +
                "sno=" + sno +
                ", score=" + score +
                ", data='" + data + '\'' +
                '}';
    }
}

//节点操作类
class SingleLinkedList {
    private Node head = new Node(0, 0, ""); //初始化头节点

    public Node getNode() {
        return head;
    }

    // add student data
    public void add(Node node) {        //数据添加
        Node temp = head;
        while (temp.next != null) {
            temp = temp.next;
        }
        temp.next = node;
    }

    //output
    public void list() {            //遍历数据进行打印
        Node temp = head.next;
        if (temp == null) {
            System.out.println("LinkedList is empty!");
        } else {
            while (temp != null) {
                System.out.println(temp);
                System.out.println();
                temp = temp.next;
            }
        }

    }

    //insert by order 2

    public void insert(Node node) {      //插入数据方式2
        Node temp = head;
        boolean flag = false;
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.sno > node.sno) {
                break;
            } else if (temp.next.sno == node.sno) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            System.out.println("Student ID ：" + node.sno + "already exists!");
            return;
        } else {
            node.next = temp.next;
            temp.next = node;
        }
    }

    public void modify(Node newNode) {           //修改操作
        Node temp = head.next;
        if (head.next == null) {
            System.out.println("LinkedList is empty,unable to modify!");
            return;
        }
        boolean flag = false;
        while (true) {
            if (temp == null) {
                break;
            }
            if (temp.sno == newNode.sno) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            temp.score = newNode.score;
            temp.data = newNode.data;
        } else {
            System.out.println("No student ID" + newNode.sno);
        }
    }

    public void delete(int sno) {        //删除操作
        Node temp = head;
        boolean flag = false;
        if (head.next == null) {
            System.out.println("LinkedList is empty,Unable to delete.");
            return;
        }
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.sno == sno) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            temp.next = temp.next.next;
        } else {
            System.out.println("No student ID:" + sno);
        }
    }

}