上个月没搞完,看这个月能不能坚持下来咯
Day1: 合并有序链表,经典题,写一个空节点当头。
/**
* 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) {
ListNode* ret = new ListNode(0,NULL);
ListNode* cur = ret;
while(l1 && l2){
if(l1->val < l2->val){
cur->next = l1;
l1 = l1->next;
}else{
cur->next = l2;
l2 = l2->next;
}
cur = cur->next;
}
if(l1){
cur->next = l1;
}
if(l2){
cur->next = l2;
}
return ret->next;
}
};