[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.

没啥好说的。

/**
* 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 *res;
ListNode *p = new ListNode(0);
res = p;
while (l1 != NULL && l2 != NULL) {
if (l1->val < l2->val) {
p->next = l1;
l1 = l1->next;
} else {
p->next = l2;
l2 = l2->next;
}
p = p->next;
}
if (l1 != NULL) {
p->next = l1;
}
if (l2 != NULL) {
p->next = l2;
}
return res->next;
}
};