LeetCodehot100-21 合并两个有序链表

class Solution { public: ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) { if(list1nullptr||list2nullptr){ return list1nullptr?list2:list1; } ListNode* headlist1-vallist2-val?list1:list2; ListNode* cur1head-next; ListNode* cur2headlist1?list2:list1; ListNode* tmphead; while(cur1!nullptrcur2!nullptr){ if(cur1-valcur2-val){ tmp-nextcur1; cur1cur1-next; } else{ tmp-nextcur2; cur2cur2-next; } tmptmp-next; } tmp-nextcur1nullptr?cur2:cur1; return head; } };递归class Solution { public: ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) { if(list1nullptr) return list2; if(list2nullptr) return list1; if(list1-vallist2-val){ list1-nextmergeTwoLists(list1-next,list2);//返回的后面的有序链表中的第一个点 return list1; } else{ list2-nextmergeTwoLists(list1,list2-next); return list2; } } };