关关的刷题日记73 – Leetcode 21. Merge Two Sorted Lists

class Solution {
public:
    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
        ListNode* head;
        if(l1==nullptr)
            return l2;
        if(l2==nullptr)
            return l1;
        if(l1->val<l2->val)
        {
            head=l1;
            head->next=mergeTwoLists(l1->next, l2);
        }
        else
        {
            head=l2;
            head->next=mergeTwoLists(l1, l2->next);
        }
        return head;
    }
};