leetcode-华为专题-21. 合并两个有序链表

 

 

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
        ListNode* H = new ListNode();
        ListNode* p = H;
        while(l1&&l2){
            if(l1->val>=l2->val){
                ListNode* tmp = new ListNode(l2->val);
                p->next = tmp;
                p = p->next;
                l2 = l2->next;
            }else{
                ListNode* tmp = new ListNode(l1->val);
                p->next = tmp;
                p = p->next;
                l1 = l1->next; 
            }
        }
        if(l1)
            p->next = l1;
        if(l2)
            p->next = l2;
        return H->next;
    }
};