Q:

Program to sort the elements of the singly linked list

belongs to collection: Singly Linked List Programs

0

Explanation

In this program, we need to sort the nodes of the given singly linked list in ascending order.

Original list:

Sorted list:

To accomplish this task, we maintain two pointers: current and index. Initially, current point to head node and index will point to node next to current. Traverse through the list till current points to null, by comparing current's data with index's data. If current's data is greater than the index's data, then swap data between them. In the above example, current will initially point to 9 and index will point to 7. Since, 9 is greater than 7, swap the data. Continue this process until the entire list is sorted in ascending order.

Algorithm

  1. Create a class Node which has two attributes: data and next. Next is a pointer to the next node in the list.
  2. Create another class SortList which has two attributes: head and tail.
  3. addNode() will add a new node to the list:
    1. Create a new node.
    2. It first checks, whether the head is equal to null which means the list is empty.
    3. If the list is empty, both head and tail will point to a newly added node.
    4. If the list is not empty, the new node will be added to end of the list such that tail's next will point to a newly added node. This new node will become the new tail of the list.
  4. sortList() will sort the nodes of the list in ascending order.
    1. Define a node current which will point to head.
    2. Define another node index which will point to node next to current.
    3. Compare data of current and index node. If current's data is greater than the index's data then, swap the data between them.
    4. Current will point to current.next and index will point to index.next.
    5. Continue this process until the entire list is sorted.
  5. display() will display the nodes present in the list:
    1. Define a node current which will initially point to the head of the list.
    2. Traverse through the list till current points to null.
    3. Display each node by making current to point to node next to it in each iteration.

Input:

 

#Adds data to the list  

sList.addNode(9);  

sList.addNode(7);  

sList.addNode(2);  

sList.addNode(5);  

sList.addNode(4);  

Output:

Original list: 9 7 2 5 4
Sorted list: 2 4 5 7 9

All Answers

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Python

#Represent a node of the singly linked list  
class Node:  
    def __init__(self,data):  
        self.data = data;  
        self.next = None;  
          
class SortList:  
    #Represent the head and tail of the singly linked list  
    def __init__(self):  
        self.head = None;  
        self.tail = None;  
          
    #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;  
              
    #sortList() will sort nodes of the list in ascending order  
    def sortList(self):  
        #Node current will point to head  
        current = self.head;  
        index = None;  
          
        if(self.head == None):  
            return;  
        else:  
            while(current != None):  
                #Node index will point to node next to current  
                index = current.next;  
                  
                while(index != None):  
                    #If current node's data is greater than index's node data, swap the data between them  
                    if(current.data > index.data):  
                        temp = current.data;  
                        current.data = index.data;  
                        index.data = temp;  
                    index = index.next;  
                current = current.next;  
                  
    #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;  
        print ""  
   
sList = SortList();  
          
#Adds data to the list  
sList.addNode(9);  
sList.addNode(7);  
sList.addNode(2);  
sList.addNode(5);  
sList.addNode(4);  
   
#Displaying original list  
print("Original list: ");  
sList.display();  
  
#Sorting list  
sList.sortList();  
   
#Displaying sorted list  
print("Sorted list: ");  
sList.display();  

 

Output:

 Original list: 
9 7 2 5 4 
Sorted list: 
2 4 5 7 9 

 

C

#include <stdio.h>  
   
//Represent a node of the singly linked list  
struct node{  
    int data;  
    struct node *next;  
};      
   
//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;  
    }  
}  
   
    //sortList() will sort nodes of the list in ascending order  
    void sortList() {  
        //Node current will point to head  
        struct node *current = head, *index = NULL;  
        int temp;  
          
        if(head == NULL) {  
            return;  
        }  
        else {  
            while(current != NULL) {  
                //Node index will point to node next to current  
                index = current->next;  
                  
                while(index != NULL) {  
                    //If current node's data is greater than index's node data, swap the data between them  
                    if(current->data > index->data) {  
                        temp = current->data;  
                        current->data = index->data;  
                        index->data = temp;  
                    }  
                    index = index->next;  
                }  
                current = current->next;  
            }      
        }  
    }  
   
//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(9);  
    addNode(7);  
    addNode(2);  
    addNode(5);  
    addNode(4);  
      
    //Displaying original list  
    printf("Original list: \n");  
    display();  
      
    //Sorting list  
    sortList();  
      
    //Displaying sorted list  
    printf("Sorted list: \n");  
    display();  
          
    return 0;  
}  

 

Output:

Original list: 
9 7 2 5 4 
Sorted list: 
2 4 5 7 9 

 

JAVA

public class SortList {  
      
    //Represent a node of the singly linked list  
    class Node{  
        int data;  
        Node next;  
          
        public Node(int data) {  
            this.data = data;  
            this.next = null;  
        }  
    }  
   
    //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;  
        }  
    }  
      
    //sortList() will sort nodes of the list in ascending order  
    public void sortList() {  
        //Node current will point to head  
        Node current = head, index = null;  
        int temp;  
          
        if(head == null) {  
            return;  
        }  
        else {  
            while(current != null) {  
                //Node index will point to node next to current  
                index = current.next;  
                  
                while(index != null) {  
                    //If current node's data is greater than index's node data, swap the data between them  
                    if(current.data > index.data) {  
                        temp = current.data;  
                        current.data = index.data;  
                        index.data = temp;  
                    }  
                    index = index.next;  
                }  
                current = current.next;  
            }      
        }  
    }  
      
    //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) {  
          
        SortList sList = new SortList();  
          
        //Adds data to the list  
        sList.addNode(9);  
        sList.addNode(7);  
        sList.addNode(2);  
        sList.addNode(5);  
        sList.addNode(4);  
          
        //Displaying original list  
        System.out.println("Original list: ");  
        sList.display();  
          
        //Sorting list  
        sList.sortList();  
          
        //Displaying sorted list  
        System.out.println("Sorted list: ");  
        sList.display();  
    }  
}  

 

Output:

Original list: 
9 7 2 5 4 
Sorted list: 
2 4 5 7 9 

 

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 SortList<T> where T : IComparable<T>{  
        //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;  
            }  
        }  
      
        //sortList() will sort nodes of the list in ascending order  
        public void sortList() {  
            //Node current will point to head  
            Node<T> current = head, index = null;  
            T temp;  
   
            if(head == null) {  
                return;  
            }  
            else {  
                while(current != null) {  
                    //Node index will point to node next to current  
                    index = current.next;  
   
                    while(index != null) {  
                        //If current node's data is greater than index's node data, swap the data between them  
                        if(current.data.CompareTo(index.data) > 0) {  
                            temp = current.data;  
                            current.data = index.data;  
                            index.data = temp;  
                        }  
                        index = index.next;  
                    }  
                    current = current.next;  
                }      
            }  
        }  
          
        //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()  
    {  
        SortList<int> sList = new SortList<int>();  
          
        //Adds data to the list  
        sList.addNode(9);  
        sList.addNode(7);  
        sList.addNode(2);  
        sList.addNode(5);  
        sList.addNode(4);  
          
        //Displaying original list  
        Console.WriteLine("Original list: ");  
        sList.display();  
          
        //Sorting list  
        sList.sortList();  
          
        //Displaying sorted list  
        Console.WriteLine("Sorted list: ");  
        sList.display();  
    }  
}  

 

Output:

Original list: 
9 7 2 5 4 
Sorted list: 
2 4 5 7 9 

 

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 SortList{  
    //Represent the head and tail of the singly linked list  
    public $head;  
    public $tail;  
    function __construct(){  
        $this->head = NULL;  
        $this->tail = NULL;  
    }  
      
    //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;  
        }  
    }  
      
    //sortList() will sort nodes of the list in ascending order  
    function sortList() {  
        //Node current will point to head  
        $current = $this->head;   
        $index = null;  
          
        if($this->head == null) {  
            return;  
        }  
        else {  
            while($current != null) {  
                //Node index will point to node next to current  
                $index = $current->next;  
                  
                while($index != null) {  
                    //If current node's data is greater than index's node data, swap the data between them  
                    if($current->data > $index->data) {  
                        $temp = $current->data;  
                        $current->data = $index->data;  
                        $index->data = $temp;  
                    }  
                    $index = $index->next;  
                }  
                $current = $current->next;  
            }      
        }  
    }  
      
    //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 SortList();  
          
//Adds data to the list  
$sList->addNode(9);  
$sList->addNode(7);  
$sList->addNode(2);  
$sList->addNode(5);  
$sList->addNode(4);  
   
//Displaying original list  
print("Original list: <br>");  
$sList->display();  
   
//Sorting list  
$sList->sortList();  
   
//Displaying sorted list  
print("Sorted list: <br>");  
$sList->display();  
?>  
</body>  
</html>  

 

Output:

 Original list: 
9 7 2 5 4 
Sorted list: 
2 4 5 7 9

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