leetcode --21. Merge Two Sorted Lists

题目：https://leetcode.com/problems/merge-two-sorted-lists/#/description

代码：class Solution {
public:
ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
ListNode *dummy = new ListNode(-1), *t = dummy;
while(l1&&l2){
if(l1->val < l2->val){
t->next = l1;
l1 = l1->next;
}else{
t->next = l2;
l2 = l2->next;
}
t = t->next;
}
t->next = l1?l1:l2;
return dummy->next;
}
};