题解 | #相反链表的合并#
相反链表的合并
https://www.nowcoder.com/practice/0222a3c31a404dd3b8c3341d189477f4
先reverse再合并就好了
/** * struct ListNode { * int val; * struct ListNode *next; * ListNode(int x) : val(x), next(nullptr) {} * }; */ class Solution { public: /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param l1 ListNode类 * @param l2 ListNode类 * @return ListNode类 */ ListNode* mergeLists(ListNode* l1, ListNode* l2) { l2 = reverseList(l2); auto start = new ListNode(-1); auto ret = start; while(l1!=nullptr&&l2!=nullptr){ if(l1->val<l2->val){ start->next = l1; l1=l1->next; start = start->next; } else { start->next = l2; l2=l2->next; start = start->next; } } if(l1==nullptr&&l2!=nullptr){ start->next = l2; } if(l1!=nullptr&&l2==nullptr){ start->next = l1; } return ret->next; } ListNode* reverseList(ListNode* head){ if(head==nullptr||head->next==nullptr) return head; auto next = head->next; head->next = nullptr; while(next->next!=nullptr){ auto tmp = next->next; next->next = head; head = next; next = tmp; } next->next = head; return next; } };