[LeetCode] Merge Two Sorted Lists

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.

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {
        ListNode node(0);
        ListNode *head = &node;
        
        while(l1 && l2)
        {
            if(l1->val > l2->val)
            {
                head->next = l2;
                l2 = l2->next;
            }
            else
            {
                head->next = l1;
                l1 = l1->next;
            }
            head = head->next;
        }
        if(l1) head->next = l1;
        else head->next = l2;
        
        return node.next;
    }
};