Java program: Search for elements in circular linked list

What are like lists and circular linked lists?

A linked list is a data structure in which each node contains two parts, data and address path. These sections point to the next node, which always creates an interconnection with the previous node. Based on this, a circular linked list is one in which the last node has an internal link with the first node, which is why this type of linked list is called a circular linked list.

In the Java environment, when we look for elements in a circular linked list, we need to create a temporary node in the linked list to point to. This way we still need to declare two variables. They are track index and track search. If the Temp node is empty at the starting point, it is important to traverse the list because it does not contain any items at this point.

How does a circular linked list work and its applications?

How circular linked lists work

With a circular linked list, the user can enter data anywhere in that particular list (in an array that is not possible in contiguous memory). In this linked list, the backward data is stored as the next address node. In this way, data points to each other in a circular fashion, forming circular chains with dynamic sizes. Here dynamic means; memory allocation will be done as per requirement.

You need to remember the following points

• Any node can be used as the starting point of the circular linked list

• The data list can be traversed starting from any random node

• There is no pointer to the first node

Application of circular linked list

• The circular linked lists used in our personal computers are multiple applications that perform their tasks simultaneously.

• is used to create a circular queue.

• Cycle through players in multiplayer games.

• For the Undo feature in Word or Photoshop applications.

Circular Linked List Algorithm

The implementation and operation method of circular linked list is very simple. There are two characteristics, data and next. To define another circular linked list we can use: head and tail. The new node is always defined by the "current node", which will point to the head of the linked list. The point moves to the next node after each iteration.

• Step 1 - Declare a newNode() with the given value.

• Step 2 - Search the invalid list.

• Step 3 − If the result is void, then head = newNode().

• Step 4 - Otherwise, define the node pointer as temp and initialize it.

Syntax of circular linked list

struct Node {int dataset; struct Node * to next;};

In this syntax, each node present in the list has a data and pointer part, which is used to create a new node when new input is received.

We can use the following methods to search for elements in a specific list -

• By adding new data to a specific list

• By searching for elements in a specific circular linked list

By adding new data to a specific linked list

Adding some new elements in the new node helps to find some specific data from the circular linked list. First, you need to insert a new node into the allocated memory. After the new data is stored, the next data can be changed to the new node. You can also store additional data at the end of the node and apply traversal.

Example

public class SearchNodearb {   
   public class Nodefind{  
      int datafall;  
      Nodefind next;  
      public Nodefind(int datafall) {  
         this.datafall = datafall;  
      }  
   }  
   public Nodefind head = null;  
   public Nodefind tail = null;  
   public void add(int datafall){   
      Nodefind newNode1 = new Nodefind(datafall);      
      if(head == null) {        
         head = newNode1;  
         tail = newNode1;  
         newNode1.next = head;  
      }  
      else {     
         tail.next = newNode1;
            
         tail = newNode1;         
         tail.next = head;  
      }  
   }  
   public void search(int element) {  
      Nodefind current = head;  
      int i = 1;  
      boolean flagon = false;  
              
      if(head == null) {  
         System.out.println("List is totally Void! So Sad!");  
      }  
      else {  
         do{  
            if(current.datafall ==  element) {  
               flagon = true;  
               break;  
            }  
            current = current.next;  
            i++;  
         }while(current != head);  
         if(flagon)  
         System.out.println("Element is present in the list with a position tag : " + i);  
         else  
         System.out.println("Element is not present in the list");  
      }  
   }  
   public static void main(String[] args) {  
      SearchNodearb cl1 = new SearchNodearb();            
      cl1.add(1000);  
      cl1.add(5000);  
      cl1.add(3);  
      cl1.add(4);  
      cl1.search(2);  
      cl1.search(5000);  
   }  
} 

Output

Element is not present in the list
Element is present in the list with a position tag: 2

By searching for elements in a specific circular linked list

First, you need to initialize a node, then counter f=0. If the head position is empty, the entire list is empty. Otherwise iterate over the complete list. If the output is zero, the element was not found in the list.

Example

public class search {
   class Nodeval {
      int data;
      Nodeval next;
      public Nodeval(int data) { this.data = data; }
   }
   public Nodeval head = null;
   public Nodeval tempo = null;
   public void addNode2001(int data){
      Nodeval new10 = new Nodeval(data);
      if (head == null) {
         head = new10;
      }
      else {
         tempo.next = new10;
      }
      tempo = new10;
      tempo.next = head;
   }
   public void find(int key){
      Nodeval temp07 = head;     
      int f = 0;
      if (head == null) {
         System.out.println("List is empty, Please Fill It ASAP");
      }
      else {
         do {
            if (temp07.data == key) {
               System.out.println(
               "element is present in the running list");
               f = 1;
               break;
            }
            temp07 = temp07.next;
         } while (temp07 != head);
         if (f == 0) {
            System.out.println(
            "element is not present here, I am sorry!");
         }
      }
   }
   public static void main(String[] args){
      search srdd = new search();
      srdd.addNode2001(5);
      srdd.addNode2001(4);
      srdd.addNode2001(3);
      srdd.addNode2001(2);
      srdd.find(2);
      srdd.find(6);
   }
} 

Output

element is present in the running list
element is not present here, I am sorry!

in conclusion

There are many advantages and disadvantages to using circular linked lists. The most important advantage is that traversal operations can be initiated from any node in the linked list. No need to use NULL, very useful for CPU cycle scheduling. But the biggest disadvantage is that if the list is not written in the correct programmatic way, it can turn into an infinite loop and the server can hang. Through this article, we learned how to find elements in a circular linked list using Java.

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