21 Merge Two Sorted Lists

链接：https://leetcode.com/problems/merge-two-sorted-lists/
问题描述：
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.

Hide Tags Linked List

这个问题就是合并从小到大的两个排序好的链表。

class Solution {public:    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {        ListNode *t=new ListNode(0),*p=t;        while(l1&&l2)        {            if(l1->val<l2->val)            {                t->next=l1;                t=l1;                l1=l1->next;            }            else            {                t->next=l2;                t=l2;                l2=l2->next;            }        }        if(l1)            t->next=l1;        if(l2)            t->next=l2;        t=p->next;        delete p;        return t;    }};