[LeetCode]21. Merge Two Sorted Lists

21. 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* newHead = new ListNode(0);
ListNode* pCur = newHead;
while(l1 || l2){
if(l1 == NULL){
pCur->next = l2;
break;
}
if(l2 == NULL){
pCur->next = l1;
break;
}
if(l1->val < l2->val){
pCur->next = l1;
l1 = l1->next;
pCur = pCur->next;
}else{
pCur->next = l2;
l2 = l2->next;
pCur = pCur->next;
}
}
return newHead->next;
}
};