Question
Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.
Thinking
節點的變化用下圖來表示
My C# Solution
/**
* Definition for singly-linked list.
* public class ListNode {
* public int val;
* public ListNode next;
* public ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode MergeTwoLists(ListNode l1, ListNode l2) {
if (l1 == null) return l2;
if (l2 == null) return l1;
ListNode dummy = new ListNode(0);
ListNode result = dummy;
while(l1 != null && l2 != null)
{
if (l1.val < l2.val)
{
dummy.next = l1;
l1 = l1.next;
}
else
{
dummy.next = l2;
l2 = l2.next;
}
dummy = dummy.next;
}
if (l1 == null) dummy.next = l2;
if (l2 == null) dummy.next = l1;
return result.next;
}
}