Question

Could somebody please help. Thanks in advance!

Merge two sorted linked lists and return it as a new list.

1) Implement a method: mergeTwoLists(…){…}

2) Use the LinkedList library in Java

3) Test your method.

Example:

Input: 1->2->4, 1->3->4

Output: 1->1->2->3->4->4

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import java.util.*;

public class Inclass1 {

    public static void main(String[] args){

        //Question 5.2
        LinkedList l1 = new LinkedList<>();
        LinkedList l2 = new LinkedList<>();

        l1.add(1);
        l1.add(2);
        l1.add(10);

        l2.add(1);
        l2.add(3);
        l2.add(4);

        LinkedList l3 = mergeTwoLists(l1, l2);

        System.out.println("Question \n******************************");

        for(int i = 0; i < l1.size(); i++){
            System.out.print(l1.get(i) + ((i == l1.size() - 1) ? "" : "->"));
        }
        System.out.println();

        for(int i = 0; i < l2.size(); i++){
            System.out.print(l2.get(i) + ((i == l2.size() - 1) ? "" : "->"));
        }
        System.out.println();

        for(int i = 0; i < l3.size(); i++){
            System.out.print(l3.get(i) + ((i == l3.size() - 1) ? "" : "->"));
        }

    }

/*    public static LinkedList mergeTwoLists(LinkedList l1, LinkedList l2){
// Inclass assignment
    }*/

Answer 1

// Inclass1.java: Java program to merge 2 sorted linked lists
import java.util.*;

public class Inclass1 {

   public static void main(String[] args){

//Question 5.2
LinkedList l1 = new LinkedList<>();
LinkedList l2 = new LinkedList<>();

l1.add(1);
l1.add(2);
l1.add(10);

l2.add(1);
l2.add(3);
l2.add(4);

LinkedList l3 = mergeTwoLists(l1, l2);

System.out.println("Question \n******************************");

for(int i = 0; i < l1.size(); i++){
System.out.print(l1.get(i) + ((i == l1.size() - 1) ? "" : "->"));
}
System.out.println();

for(int i = 0; i < l2.size(); i++){
System.out.print(l2.get(i) + ((i == l2.size() - 1) ? "" : "->"));
}
System.out.println();

for(int i = 0; i < l3.size(); i++){
System.out.print(l3.get(i) + ((i == l3.size() - 1) ? "" : "->"));
}

}

// method to merge and return two sorted linked list of integers into a single linked list
   public static LinkedList mergeTwoLists(LinkedList l1, LinkedList l2) {
         
       LinkedList merged = new LinkedList<>(); // create an empty linked list
       int i,j;
         
       // loop that continues till the end of list l1 and l2
       for(i=0,j=0;i<l1.size() && j < l2.size();)
       {
           // if ith element of l1 <= jth element of l2, insert ith element of l1 into merged list and increment i
           // cast the element to Comparable so that both can be compared
           if(((Comparable)l1.get(i)).compareTo(l2.get(j)) <=0)
           {
               merged.add(l1.get(i));
               i++;
           }
           else // if ith element of l1 > jth element of l2, insert jth element of l2 into merged list and increment j
           {
               merged.add(l2.get(j));
               j++;
           }
       }
         
       // if there are elements remaining in l1, insert them in merged in the order appearing in l1
       for(;i<l1.size();i++)
           merged.add(l1.get(i));
         
       // if there are elements remaining in l2, insert them in merged in the order appearing in l2
       for(;j<l2.size();j++)
           merged.add(l2.get(j));
         
       return merged; // return the merged list
   }
  
}
//end of Inclass1.java

Output: