在单向链表中插入新节点的程序

2025年3月17日 | 阅读11分钟

说明

在此程序中，我们将创建一个单链表，并在列表的中间插入一个新节点。为此，我们将计算列表的大小，然后将其除以2以获得需要插入新节点的中间点。

Program to insert a new node at the middle of the singly linked list

考虑上图；节点1代表原始列表的头部。令节点New为需要在列表中间添加的新节点。首先，我们计算大小，在本例中为4。因此，为了得到中间点，我们将其除以2并存储在变量count中。节点current将指向head。首先，我们遍历列表，直到current指向中间位置。定义另一个节点temp，它指向current后面的节点。在current和temp之间插入New节点。

算法

创建一个名为 Node 的类，它有两个属性：data 和 next。Next 是指向链表中下一个节点的指针。
创建另一个名为InsertMid的类，该类具有三个属性：head、tail和size，它们跟踪列表中存在的节点数量。
addNode() 将向列表添加一个新节点
1. 创建一个新节点。
2. 它首先检查 head 是否等于 null，这意味着列表为空。
3. 如果列表为空，则 head 和 tail 都将指向新添加的节点。
4. 如果列表不为空，新节点将添加到列表末尾，使得 tail 的 next 指向新添加的节点。此新节点将成为列表的新 tail。
addInMid()将在列表的中间添加一个新节点
1. 它首先检查 head 是否等于 null，这意味着列表为空。
2. 如果列表为空，则 head 和 tail 都将指向新添加的节点。
3. 如果列表不为空，则计算列表的大小并将其除以2以获得列表的中间点。
4. 定义节点current，它将遍历列表，直到current指向中间节点。
5. 定义另一个节点 temp，它将指向 current 的下一个节点。
6. 新节点将插入在 current 之后和 temp 之前，使得 current 指向新节点，新节点指向 temp。
display() 将显示列表中存在的节点
1. 定义一个节点 current，它最初将指向列表的 head。
2. 遍历列表直到 current 指向 null。
3. 通过使 current 在每次迭代中指向它的下一个节点来显示每个节点。

解决方案

Python

#Represent a node of the singly linked list
class Node:
    def __init__(self,data):
        self.data = data;
        self.next = None;
        
class InsertMid:
    #Represent the head and tail of the singly linked list
    def __init__(self):
        self.head = None;
        self.tail = None;
        self.size = 0;
        
    #addNode() will add a new node to the list
    def addNode(self, data):
        #Create a new node
        newNode = Node(data);
        
        #Checks if the list is empty
        if(self.head == None):
            #If list is empty, both head and tail will point to new node
            self.head = newNode;
            self.tail = newNode;
        else:
            #newNode will be added after tail such that tail's next will point to newNode
            self.tail.next = newNode;
            #newNode will become new tail of the list
            self.tail = newNode;
        #Size will count the number of nodes present in the list
        self.size = self.size + 1;
        
    #This function will add the new node at the middle of the list.
    def addInMid(self, data):
        #Create a new node
        newNode = Node(data);
        
        #Checks if the list is empty
        if(self.head == None):
            #If list is empty, both head and tail would point to new node
            self.head = newNode;
            self.tail = newNode;
        else:
            #Store the mid position of the list
            count = (self.size//2) if(self.size % 2 == 0) else ((self.size+1)//2);
            #Node temp will point to head
            temp = self.head;
            current = None;
            
            #Traverse through the list till the middle of the list is reached
            for i in range(0, count):
                #Node current will point to temp
                current = temp;
                #Node temp will point to node next to it.
                temp = temp.next;
            
            #current will point to new node
            current.next = newNode;
            #new node will point to temp
            newNode.next = temp;
        self.size = self.size + 1;
            
    #display() will display all the nodes present in the list
    def display(self):
        #Node current will point to head
        current = self.head;
        
        if(self.head == None):
            print("List is empty");
            return;
            
        while(current != None):
            #Prints each node by incrementing pointer
            print(current.data)
            current = current.next;
        
 
sList = InsertMid();
        
#Adds data to the list
sList.addNode(1);
sList.addNode(2);
 
print("Original list: ");
sList.display();
 
#Inserting node '3' in the middle
sList.addInMid(3);
print( "Updated List: ");
sList.display();
 
#Inserting node '4' in the middle
sList.addInMid(4);
print("Updated List: ");
sList.display();

输出

 Original list: 
1 2 
Updated List: 
1 3 2 
Updated List: 
1 3 4 2

C

#include <stdio.h>
 
//Represent a node of the singly linked list
struct node{
    int data;
    struct node *next;
};    
 
int size;
//Represent the head and tail of the singly linked list
struct node *head, *tail = NULL;
 
//addNode() will add a new node to the list
void addNode(int data) {
    //Create a new node
    struct node *newNode = (struct node*)malloc(sizeof(struct node));
    newNode->data = data;
    newNode->next = NULL;
    
    //Checks if the list is empty
    if(head == NULL) {
        //If list is empty, both head and tail will point to new node
        head = newNode;
        tail = newNode;
    }
    else {
        //newNode will be added after tail such that tail's next will point to newNode
        tail->next = newNode;
        //newNode will become new tail of the list
        tail = newNode;
    }
    //Size will count the number of nodes present in the list
    size++;
}
 
//This function will add the new node at the middle of the list.
void addInMid(int data){
    //Create a new node
    struct node *newNode = (struct node*)malloc(sizeof(struct node));
    newNode->data = data;
    newNode->next = NULL;
    
    //Checks if the list is empty
    if(head == NULL) {
        //If list is empty, both head and tail would point to new node
        head = newNode;
        tail = newNode;
    }
    else {
        struct node *temp, *current;
        //Store the mid position of the list
        int count = (size % 2 == 0) ? (size/2) : ((size+1)/2);
        //Node temp will point to head
        temp = head;
        current = NULL;
 
        //Traverse through the list till the middle of the list is reached
        for(int i = 0; i < count; i++) {
            //Node current will point to temp
            current = temp;
            //Node temp will point to node next to it.
            temp = temp->next;
        }
        
        //current will point to new node
        current->next = newNode;
        //new node will point to temp
        newNode->next = temp;
    }
    size++;
}
    
//display() will display all the nodes present in the list
void display() {
    //Node current will point to head
    struct node *current = head;
    
    if(head == NULL) {
        printf("List is empty\n");
        return;
    }
    while(current != NULL) {
        //Prints each node by incrementing pointer
        printf("%d ", current->data);
        current = current->next;
    }
    printf("\n");
}
    
int main()
{
    //Adds data to the list
    addNode(1);
    addNode(2);
    
    printf("Original list: \n");
    display();
    
    //Inserting node '3' in the middle
    addInMid(3);
    printf( "Updated List: \n");
    display();
    
    //Inserting node '4' in the middle
    addInMid(4);
    printf("Updated List: \n");
    display();
    
    return 0;
}

输出

Original list: 
1 2 
Updated List: 
1 3 2 
Updated List: 
1 3 4 2

JAVA

public class InsertMid {
    
    //Represent a node of the singly linked list
    class Node{
        int data;
        Node next;
        
        public Node(int data) {
            this.data = data;
            this.next = null;
        }
    }
 
    public int size;
    //Represent the head and tail of the singly linked list
    public Node head = null;
    public Node tail = null;
    
    //addNode() will add a new node to the list
    public void addNode(int data) {
        //Create a new node
        Node newNode = new Node(data);
        
        //Checks if the list is empty
        if(head == null) {
            //If list is empty, both head and tail will point to new node
            head = newNode;
            tail = newNode;
        }
        else {
            //newNode will be added after tail such that tail's next will point to newNode
            tail.next = newNode;
            //newNode will become new tail of the list
            tail = newNode;
        }
        //Size will count the number of nodes present in the list
        size++;
    }
    
    //This function will add the new node at the middle of the list.
    public void addInMid(int data){
        //Create a new node
        Node newNode = new Node(data);
        
        //Checks if the list is empty
        if(head == null) {
            //If list is empty, both head and tail would point to new node
            head = newNode;
            tail = newNode;
        }
        else {
            Node temp, current;
            //Store the mid position of the list
            int count = (size % 2 == 0) ? (size/2) : ((size+1)/2);
            //Node temp will point to head
            temp = head;
            current = null;
 
            //Traverse through the list till the middle of the list is reached
            for(int i = 0; i < count; i++) {
                //Node current will point to temp
                current = temp;
                //Node temp will point to node next to it.
                temp = temp.next;
            }
            
            //current will point to new node
            current.next = newNode;
            //new node will point to temp
            newNode.next = temp;
        }
        size++;
    }
    
    //display() will display all the nodes present in the list
    public void display() {
        //Node current will point to head
        Node current = head;
        if(head == null) {
            System.out.println("List is empty");
            return;
        }
        
        while(current != null) {
            //Prints each node by incrementing pointer
            System.out.print(current.data + " ");
            current = current.next;
        }
        System.out.println();
    }
    
    public static void main(String[] args) {
        
        InsertMid sList = new InsertMid();
        
        //Adds data to the list
        sList.addNode(1);
        sList.addNode(2);
        
        System.out.println("Original list: ");
        sList.display();
        
        //Inserting node '3' in the middle
        sList.addInMid(3);
        System.out.println( "Updated List: ");
        sList.display();
        
        //Inserting node '4' in the middle
        sList.addInMid(4);
        System.out.println("Updated List: ");
        sList.display();
    }
}

输出

Original list: 
1 2 
Updated List: 
1 3 2 
Updated List: 
1 3 4 2

C#

using System;
                    
public class CreateList
{
    //Represent a node of the singly linked list
    public class Node<T>{
        public T data;
        public Node<T> next;
        
        public Node(T value) {
            data = value;
            next = null;
        }
    }
        
    public class InsertMid<T>{
        public int size;
        //Represent the head and tail of the singly linked list
        public Node<T> head = null;             
         public Node<T> tail = null;
    
        //addNode() will add a new node to the list
        public void addNode(T data) {
            //Create a new node
            Node<T> newNode = new Node<T>(data);
 
            //Checks if the list is empty
            if(head == null) {
                //If list is empty, both head and tail will point to new node
                head = newNode;
                tail = newNode;
            }
            else {
                //newNode will be added after tail such that tail's next will point to newNode
                tail.next = newNode;
                //newNode will become new tail of the list
                tail = newNode;
            }
            //Size will count the number of nodes present in the list
            size++;
        }
 
        //This function will add the new node at the middle of the list.
        public void addInMid(T data){
            //Create a new node
            Node<T> newNode = new Node<T>(data);
 
            //Checks if the list is empty
            if(head == null) {
                //If list is empty, both head and tail would point to new node
                head = newNode;
                tail = newNode;
            }
            else {
                Node<T> temp, current;
                //Store the mid position of the list
                int count = (size % 2 == 0) ? (size/2) : ((size+1)/2);
                //Node temp will point to head
                temp = head;
                current = null;
 
                //Traverse through the list till the middle of the list is reached
                for(int i = 0; i < count; i++) {
                    //Node current will point to temp
                    current = temp;
                    //Node temp will point to node next to it.
                    temp = temp.next;
                }
 
                //current will point to new node
                current.next = newNode;
                //new node will point to temp
                newNode.next = temp;
            }
            size++;
        }
 
        //display() will display all the nodes present in the list
        public void display() {
            //Node current will point to head
            Node<T> current = head;
            if(head == null) {
                Console.WriteLine("List is empty");
                return;
            }
 
            while(current != null) {
                //Prints each node by incrementing pointer
                Console.Write(current.data + " ");
                current = current.next;
            }
            Console.WriteLine();
        }
    }
    
    public static void Main()
    {
        InsertMid<int> sList = new InsertMid<int>();
        
        //Adds data to the list
        sList.addNode(1);
        sList.addNode(2);
        
        Console.WriteLine("Original list: ");
        sList.display();
        
        //Inserting node '3' in the middle
        sList.addInMid(3);
        Console.WriteLine( "Updated List: ");
        sList.display();
        
        //Inserting node '4' in the middle
        sList.addInMid(4);
        Console.WriteLine("Updated List: ");
        sList.display();
    }
}

输出

Original list: 
1 2 
Updated List: 
1 3 2 
Updated List: 
1 3 4 2

PHP

<!DOCTYPE html>
<html>
<body>
<?php
//Represent a node of singly linked list
class Node{
    public $data;
    public $next;
    
    function __construct($data){
        $this->data = $data;
        $this->next = NULL;
    }
}
class InsertMid{
    //Represent the head and tail of the singly linked list
    public $head;
    public $tail;
    function __construct(){
        $this->head = NULL;
        $this->tail = NULL;
        $this->size = 0;
    }
    
    //addNode() will add a new node to the list
    function addNode($data) {
        //Create a new node
        $newNode = new Node($data);
        
        //Checks if the list is empty
        if($this->head == null) {
            //If list is empty, both head and tail will point to new node
            $this->head = $newNode;
            $this->tail = $newNode;
        }
        else {
            //newNode will be added after tail such that tail's next will point to newNode
            $this->tail->next = $newNode;
            //newNode will become new tail of the list
            $this->tail = $newNode;
        }
        //Size will count the number of nodes present in the list
        $this->size++;
    }
    
    //This function will add the new node at the middle of the list.
    function addInMid($data){
        //Create a new node
        $newNode = new Node($data);
        
        //Checks if the list is empty
        if($this->head == null) {
            //If list is empty, both head and tail would point to new node
            $this->head = $newNode;
            $this->tail = $newNode;
        }
        else {
            //Store the mid position of the list
            $count = ($this->size % 2 == 0) ? ($this->size/2) : (($this->size+1)/2);
            //Node temp will point to head
            $temp = $this->head;
            $current = null;
 
            //Traverse through the list till the middle of the list is reached
            for($i = 0; $i < $count; $i++) {
                //Node current will point to temp
                $current = $temp;
                //Node temp will point to node next to it.
                $temp = $temp->next;
            }
            
            //current will point to new node
            $current->next = $newNode;
            //new node will point to temp
            $newNode->next = $temp;
        }
        $this->size++;
    }
    
    //display() will display all the nodes present in the list
    function display() {
        //Node current will point to head
        $current = $this->head;
        
        if($this->head == NULL) {
            print("List is empty <br>");
            return;
        }
        while($current != NULL) {
            //Prints each node by incrementing pointer
            print($current->data . " ");
            $current = $current->next;
        }
        print("<br>");
    }
}
 
$sList = new InsertMid();
 
//Adds data to the list
$sList->addNode(1);
$sList->addNode(2);
 
print("Original list: <br>");
$sList->display();
 
//Inserting node '3' in the middle
$sList->addInMid(3);
print( "Updated List: <br>");
$sList->display();
 
//Inserting node '4' in the middle
$sList->addInMid(4);
print("Updated List: <br>");
$sList->display();
?>
</body>
</html>

输出

Original list: 
1 2 
Updated List: 
1 3 2 
Updated List: 
1 3 4 2

下一主题#

在单向链表中插入新节点的程序

说明

算法

解决方案

Python

C

JAVA

C#

PHP

联系信息

关注我们

教程

面试题

在线编译器

Python

Java

.Net Framework

AI, ML and Data Science

Cloud Technology

B.Tech and MCA

Web Technology

PHP

Software Testing

Technical Interview

Java Interview

Python

Web Interview

Database Interview

B.Tech / MCA

Important Interview

Software Testing Interview

Company Interviews

Online Compilers

Multiple Choice Questions

程序

在单向链表中插入新节点的程序

说明

算法

解决方案

Python

C

JAVA

C#

PHP

相关帖子

查找梯形面积和周长的程序

查找二叉树中最大元素的程序

查找半圆面积和周长的程序

使用链表实现二叉树的程序

计算 CGPA 百分比的程序

计算二叉树奇数层和偶数层节点之和差的程序

在循环链表中搜索元素的程序

从单链表中查找最大值和最小值节点的程序

在单链表中搜索元素的程序

在双向链表中搜索元素的程序

订阅 Tpoint Tech

联系信息

关注我们

教程

面试题

在线编译器