Interview Question: Merge two sorted singly linked lists without creating new nodes

Question

This is a programming question asked during a written test for an interview. \"You have two singly linked lists that are already sorted, you have to merge them and return a

Answer 1

Here is a complete working example that uses the linked list implemented java.util. You can just copy paste the code below inside a main() method.

        LinkedList dList1 = new LinkedList();
        LinkedList dList2 = new LinkedList();
        LinkedList dListMerged = new LinkedList();

        dList1.addLast(1);
        dList1.addLast(8);
        dList1.addLast(12);
        dList1.addLast(15);
        dList1.addLast(85);

        dList2.addLast(2);
        dList2.addLast(3);
        dList2.addLast(12);
        dList2.addLast(24);
        dList2.addLast(85);
        dList2.addLast(185);

        int i = 0;
        int y = 0;
        int dList1Size = dList1.size();
        int dList2Size = dList2.size();
        int list1Item = dList1.get(i);
        int list2Item = dList2.get(y);
        while (i < dList1Size || y < dList2Size) {

            if (i < dList1Size) {

                if (list1Item <= list2Item || y >= dList2Size) {
                    dListMerged.addLast(list1Item);
                    i++;
                    if (i < dList1Size) {
                        list1Item = dList1.get(i);
                    }
                }
            }


            if (y < dList2Size) {

                if (list2Item <= list1Item || i >= dList1Size) {
                    dListMerged.addLast(list2Item);
                    y++;
                    if (y < dList2Size) {
                        list2Item = dList2.get(y);
                    }
                }
            }

        }

        for(int x:dListMerged)
        {
            System.out.println(x);
        }