LeetCode -- Merge Two sorted lists

LeetCode -- Merge Two sorted lists
Description:
Merge two sorted linked lists and return it as a new list. The new list shoshould be made by splicing together the nodes of the first two lists.


Merge two sorted linked lists.


Ideas:
Merge the linked list l2 into l1 and traverse l2 one by one
If l1 is not the last one:
L1 <= l2 & l2 <= l1.next: Remove l2 and put l2 at l1.next
L2 <l1: replace l2.next = l1 with the header Node
Else: l1 = l1.next
If l1 is the last node:
L2> l1: l1.next = l2
Else: replace l2.next = l1 with the header Node




Implementation Code:

/** * 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;}// merge l2 into l1ListNode head = l1;while(l2 != null){if(l1.next != null){if(l2.val >= l1.val && l2.val <= l1.next.val){var t = Remove(ref l2);t.next = l1.next;l1.next = t;}else if(l2.val < l1.val){var t = Remove(ref l2);t.next = l1;head = t;l1 = t;}else{l1 = l1.next;}}else{if(l1.val < l2.val){l1.next = Remove(ref l2);}else{var t = Remove(ref l2);t.next = l1;head = t;l1 = t;}}}return head;    }        private ListNode Remove(ref ListNode n)    {            ListNode t = new ListNode(n.val);    if(n.next == null){    n = null;    }    else{    n.val = n.next.val;    n.next = n.next.next;    }    return t;    }}