Added Linked List in java with basic opertiaons(search,delete,insert,…

Java/singly-linked-list/LengthOfLinkedList.java

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+class Node{
+    int data;
+    Node next;
+    Node(int data1, Node next1){
+        this.data=data1;
+        this.next=next1;
+    }
+    Node(int data1){
+        this.data=data1;
+        this.next=null;
+    }
+};
+public class LengthOfLinkedList {
+    // Function to calculate the length of a linked list
+    private static int lengthOfLL(Node head){
+        int cnt=0;
+        Node temp=head;
+        // Traverse the linked list and count nodes
+        while(temp!=null){
+            temp = temp.next;
+            cnt++;// increment cnt for every node traversed
+        }
+        return cnt;
+    }
+    public static void main(String[] args) {
+        int[]arr={2,5,8,7};
+        Node head = new Node(arr[0]);
+        head.next= new Node(arr[1]);
+        head.next.next= new Node(arr[2]);
+        head.next.next.next= new Node(arr[3]);
+        // Print the length of the linked list
+        System.out.println(lengthofaLL(head));
+    }
+}

Java/singly-linked-list/SearchInLinkedList.java

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+// Node class represents a node in a linked list
+class Node {
+    int data;      // Data stored in the node
+    Node next;     // Reference to the next node in the list
+
+    // Constructor with both data and next node as parameters
+    Node(int data1, Node next1) {
+        this.data = data1;
+        this.next = next1;
+    }
+
+    // Constructor with only data as a parameter, sets next to null
+    Node(int data1) {
+        this.data = data1;
+        this.next = null;
+    }
+}
+
+// LinkedList class contains utility methods for linked list operations
+public class SearchInLinkedList {
+
+    // Function to check if a given element is present in the linked list
+    public static int checkifPresent(Node head, int desiredElement) {
+        Node temp = head;
+
+        // Traverse the linked list
+        while (temp != null) {
+            // Check if the current node's data is equal to the desired element
+            if (temp.data == desiredElement)
+                return 1;  // Return 1 if the element is found
+
+            // Move to the next node
+            temp = temp.next;
+        }
+
+        return 0;  // Return 0 if the element is not found in the linked list
+    }
+
+    // Main function
+    public static void main(String[] args) {
+        // Create a linked list: 1 -> 2 -> 3
+        int[] arr = {1, 2, 3};
+        Node head = new Node(arr[0]);
+        head.next = new Node(arr[1]);
+        head.next.next = new Node(arr[2]);
+
+        int val = 3;  // Element to be checked for presence in the linked list
+
+        // Call the checkifPresent function and print the result
+        System.out.print(checkifPresent(head, val));
+    }
+}

Java/singly-linked-list/deletelastnode.java

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+// Node class definition
+class Node {
+    int data;
+    Node next;
+    // Constructor with both data and next pointer
+    Node(int data1, Node next1) {
+        this.data = data1;
+        this.next = next1;
+    }
+    // Constructor with only data (next pointer set to null)
+    Node(int data1) {
+        this.data = data1;
+        this.next = null;
+    }
+}
+// LinkedList class
+public class DeleteLastNode {
+    // Function to delete the tail of the linked list
+    private static Node deleteTail(Node head) {
+        // Check if the linked list is empty or has only one node
+        if (head == null || head.next == null)
+            return null;
+        // Create a temporary pointer for traversal
+        Node temp = head;
+        // Traverse the list until the second-to-last node
+        while (temp.next.next != null) {
+            temp = temp.next;
+        }
+        // Nullify the connection from the second-to-last node to delete the last node
+        temp.next = null;
+        // Return the updated head of the linked list
+        return head;
+    }
+    // Function to print the linked list
+    private static void printLL(Node head) {
+        while (head != null) {
+            System.out.print(head.data + " ");
+            head = head.next;
+        }
+    }
+    // Main method
+    public static void main(String[] args) {
+        // Initialize an array with integer values
+        int[] arr = {2, 5, 8, 7};
+        // Create the linked list with nodes initialized with array values
+        Node head = new Node(arr[0]);
+        head.next = new Node(arr[1]);
+        head.next.next = new Node(arr[2]);
+        head.next.next.next = new Node(arr[3]);
+        // Delete the tail of the linked list
+        head = deleteTail(head);
+        // Print the modified linked list
+        printLL(head);
+    }
+}

Java/singly-linked-list/insertathead.java

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+import java.util.*;
+
+// Node class to represent a linked list node
+class Node {
+    public int data;
+    public Node next;
+
+    // Constructor with both data and next node
+    public Node(int data1, Node next1) {
+        data = data1;
+        next = next1;
+    }
+
+    // Constructor with only data (assuming next is initially null)
+    public Node(int data1) {
+        data = data1;
+        next = null;
+    }
+}
+
+public class InsertAtHead {
+    // Function to print the linked list
+    public static void printLL(Node head) {
+        while (head != null) {
+            System.out.print(head.data + " ");
+            head = head.next;
+        }
+    }
+
+    // Function to insert a new node at the head of the linked list
+    public static Node insertHead(Node head, int val) {
+        Node temp = new Node(val, head);
+        return temp;
+    }
+
+    public static void main(String[] args) {
+        // Sample array and value for insertion
+        List<Integer> arr = Arrays.asList(12, 8, 5, 7);
+        int val = 100;
+
+        // Creating a linked list with initial elements from the array
+        Node head = new Node(arr.get(0));
+        head.next = new Node(arr.get(1));
+        head.next.next = new Node(arr.get(2));
+        head.next.next.next = new Node(arr.get(3));
+
+        // Inserting a new node at the head of the linked list
+        head = insertHead(head, val);
+
+        // Printing the linked list
+        printLL(head);
+    }
+}