合并两个排好序的链表,并返回这个新链表。
新链表应该由这两个链表的头部拼接而成。
Merge two sorted linked lists and return it as a new list.
The new list should be made by splicing together the nodes of the first two lists.
/** * 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) { if(l2 == NULL) { return l1; } if(l1 == NULL) { return l2; } if(l1->val > l2->val) { ListNode* temp = l2; temp->next = mergeTwoLists(l1, l2->next); return temp; } else { ListNode* temp = l1; temp->next = mergeTwoLists(l1->next, l2); return temp; } } };