//将两个升序链表合并为一个新的 升序 链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。
//这段代码为什么错了?
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) {}
};
int panA(ListNode* l1, ListNode* l2){
if (l1->val == l2->val)
return 0;
else if (l1->val >l2->val)
return 1;
else
return -1;
}
class Solution {
public:
ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
ListNode* head = new ListNode();
ListNode* pre = head;
while (l1&&l2)
{
int s = panA(l1, l2);
switch (s)
{
case 1:
pre->next = new ListNode(l2->val);
l2 = l2->next;
break;
case 0:
pre->next = new ListNode(l1->val);
l1 = l1->next;
break;
case -1:
pre->next = new ListNode(l1->val);
l1 = l1->next;
break;
default:
break;
}
}
if (l1)
pre->next = l1;
if(l2)
pre->next = l2;
return head->next;
}
};