题目链接
25. 合并两个排序的链表
思路分析
利用归并排序的归并思想
/**
* 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) {
std::ios::sync_with_stdio(false);
auto dummy = new ListNode(-1);
auto cur = dummy;
while(l1 && l2){
if(l1->val <= l2->val){
cur->next = l1;
cur = l1;
l1 = l1->next;
}else{
cur->next = l2;
cur = l2;
l2 = l2->next;
}
}
if(l1) cur->next = l1;
else cur->next = l2;
auto res = dummy->next;
delete dummy;
return res;
}
};