LeetCode 21. Merge Two Sorted Lists 合併兩個有序連結串列
阿新 • • 發佈:2019-01-25
/**
* 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) {
if(l1==nullptr)
return l2;
if(l2==nullptr)
return l1;
ListNode l3(-1);
ListNode *p=&l3;
for(;l1!=nullptr&&l2!=nullptr;p=p->next)
{
if(l1->val>l2->val)
{
p->next=l2;
l2=l2->next;
}
else
{
p->next=l1;
l1=l1->next;
}
}
p->next=l1==nullptr?l2:l1;
return l3.next;
}
};