题目描述

blablabla

样例

class Solution {
public:
    ListNode* merge(ListNode* l1, ListNode* l2) {
        ListNode* head;
        auto p = l1;
        auto q = l2;
        if(!l1) return l2;
        if(!l2) return l1;
        if(l1->val>l2->val){
            head = l2;
            q = q->next;
        }else{
            head = l1;
            p = p->next;
        }
        auto t = head;
        while(p&&q){
        if(p->val>q->val){
            t->next = q;
            t = t->next;
            q = q->next;
        }else{
            t->next = p;
            t = t->next;
            p = p->next;
        }
        }
        if(p) t->next = p;
        if(q) t->next = q;
        return head;
    }  

};