题目描述

法一 顺序合并

class Solution {
public:ListNode* mergeTwoLists(ListNode* l1, ListNode* l2){ListNode* dummy = new ListNode(-1);   //创建一个新的头节点 ListNode *cur=dummy, *aPtr = l1, *bPtr = l2;while(aPtr && bPtr){if(aPtr->val < bPtr->val){dummy->next = aPtr;aPtr = aPtr->next;} else {dummy->next = bPtr;bPtr = bPtr->next;}dummy = dummy->next;}dummy->next = aPtr ? aPtr : bPtr;return cur->next;	}ListNode* mergeKLists(vector<ListNode*>& lists){ListNode* ans = nullptr;for(int i=0;i<lists.size();i++)	{ans = mergeTwoLists(ans, lists[i]);}return ans;}
};