Question

Use Java programming to implement the following:

Implement the following methods in the UnorderedList class for managing a singly linked list that cannot contain duplicates.

• Default constructor
  Create an empty list i.e., head is null.
• boolean insert(int data)
  Insert the given data into the end of the list. If the insertion is successful, the function returns true; otherwise, returns false.
• boolean delete(int data)
  Delete the node that contains the given data from the list. If the deletion is successful, the function returns true; otherwise, returns false.
• int find(int data)
  Search and return the index to the node that contains the data. Note that the index starts from 0. If it is not found, return -1.
• int count()
  Count and return the number of nodes in the list
• String toString()
  Return the string representation of this List where all data in the list are enclosed in square brackets [ ].

Then write the program that accepts a sequence of commands and print out the number of successful insertions, the number of successful deletions, the number of successful searches (through the “find” command), the number of items remaining in the list after executing all commands and the final contents of the list.

There are 3 commands which are “insert”, “delete” and “find”.

Input

Line 1: The number of transactions m on the list, where 1  m 200.

Line 2 to m+1: A string command (“insert”, “delete”, “find”) followed by an integer n (separated by a space).

• • “insert” means insert n into the list
• • “delete” means delete n from the list
• • “find” means find n in the list

Output

Line 1: Display 4 integers (each number is separated by a space) which are:

• the number of successful insertions,
• the number of successful deletions,
• the number of items found (from the command “find”), and
• the number of items remaining in the list

Line 2: The final contents of the list

Sample Input	Sample Output
3 insert 1 delete 5 find 2	1 0 0 1 [ 1 ]
8 find 10 insert 3 insert 2 insert 1 delete 4 delete 3 insert 1 find 2	3 1 1 2 [ 2 1 ]

Answer 1

Hello, I am writing the code in java with comments as you mentioned please go through it and if you have any doubt, feel free to ask in comment and if you like this answer, It will be helpful for me by your upvote.

Thank you and enjoy your answer,

import java.util.Scanner;
import java.lang.String;
class LinkedList 
{ 
  Node head; // head of list 

  /* Linked list Node*/
  class Node 
  { 
    int data; 
    Node next; 
    Node(int d) {data = d; next = null; } 
  } 

  /* inserts a new node at the end. This method is 
  defined inside LinkedList class shown above */
  public boolean insert(int new_data) 
  { 
    Node new_node = new Node(new_data); 

    /* If the Linked List is empty, then make the 
      new node as head */
    if (head == null) 
    { 
      head = new Node(new_data); 
      return true; 
    } 

    if(find(new_data)){
      return false;
    }

    /* This new node is going to be the last node, so 
      make next of it as null */
    new_node.next = null; 

    /* Else traverse till the last node */
    Node last = head; 
    while (last.next != null) 
      last = last.next; 

    /* Change the next of last node */
    last.next = new_node; 
    return true; 
  } 

  //Checks whether the value x is present in linked list 
  public boolean find(int x) 
  { 
      Node current = head;    //Initialize current 
      while (current != null) 
      { 
          if (current.data == x) 
              return true;    //data found 
          current = current.next; 
      } 
      return false;    //data not found 
  } 

  /* for delete the node with given value */
  public boolean delete(int key)
    {
        // Store head node
        Node temp = head, prev = null;
 
        // If head node itself holds the key to be deleted
        if (temp != null && temp.data == key)
        {
            head = temp.next; // Changed head
            return true;
        }
 
        // Search for the key to be deleted, keep track of the
        // previous node as we need to change temp.next
        while (temp != null && temp.data != key)
        {
            prev = temp;
            temp = temp.next;
        }    
 
        // If key was not present in linked list
        if (temp == null) return false;
 
        // Unlink the node from linked list
        prev.next = temp.next;
        return true;
    }

  /* This function prints contents of linked list starting from 
    the given node */
  public void printList() 
  { 
    Node tnode = head;
    System.out.print("[ ");
    while (tnode != null) 
    { 
      System.out.print(tnode.data+" "); 
      tnode = tnode.next; 
    }
    System.out.print("]");
  } 

  /* method to count the number of node in list */

  public int count()
  {
    int count = 0;
    Node tnode = head;
    // while
    while (tnode != null) 
    { 
      tnode = tnode.next; 
      count = count + 1;
    }
    return count;
  }

  /* Driver program to test above functions. */
  public static void main(String[] args) 
  { 
    /* Start with the empty list */
    LinkedList mylist = new LinkedList(); 

    Scanner myObj = new Scanner(System.in);
    /* taking the number from user*/
    int m = myObj.nextInt();
    int insert = 0, find = 0, delete = 0;
    for(int i = 0 ; i< m; i++)
    {
      
      Scanner myObj1 = new Scanner(System.in);
      // taking the input from user
      String input = myObj1.nextLine();

      String[] strList = input.split(" ");

      int value = Integer.parseInt(strList[1]);

      if(strList[0].equals("insert")){
        if(mylist.insert(value)){
          insert = insert + 1;
        }
      }
      if(strList[0].equals("find")){
        if(mylist.find(value)){
          find = find + 1;
        }
      }
      if(strList[0].equals("delete")){
        if(mylist.delete(value)){
          delete = delete + 1;
        }
      }
    } 

    System.out.println(insert + " " + delete + " " + find + " "+ mylist.count());
 
    mylist.printList(); 
  } 
} 

// Output:

Thank you, Have a nice day.