/*
* February 2, 2015
*
* code reference:
* http://stackoverflow.com/questions/10707352/interview-merging-two-sorted-singly-linked-list
*
* Try to use recursive function, easy and quickly, and bug free.
* two singly linked lists that are already sorted, assuming that
* sorting is ascending order
*
* Julia's analysis:
* 1. Bug001:
* You have to make sure that function will not generate null exception;
* 2. Assuming that two lists are sorted in ascending order;
* 3. Do not create any new extra node.
*
* Talk about recursive function design tips:
* 1. First, check base cases - do not bring into null exception: list1.value
* 2. Divide and conquer, or only do the work for first node, and then, use recursive calls.
*/
public static Node MergeLists(Node list1, Node list2)
{
if (list1 == null) return list2;
if (list2 == null) return list1;
if (list1.value <= list2.value)
{
list1.next = MergeLists(list1.next, list2);
return list1;
}
else
{
list2.next = MergeLists(list1, list2.next);
return list2;
}
}
static void Main(string[] args)
{
Node l1 = new Node(1);
l1.next = new Node(3);
l1.next.next = new Node(5);
Node l2 = new Node(2);
l2.next = new Node(4);
l2.next.next = new Node(6);
Node newList = MergeLists(l1, l2);
}