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.

合並兩個有序鏈表

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

merge-two-sorted-lists合並鏈表