leetcode | Merge Two Sorted Lists

Merge Two Sorted Lists

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.

C实现

/*** Definition for singly-linked list.* struct ListNode {* int val;* struct ListNode *next;* };*///时间复杂度O(min(m, n)) 空间复杂度O(1)
struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {if (l1 == NULL || l2 == NULL)return (l1 == NULL) ? l2 : l1;struct ListNode* dummy = (struct ListNode*)malloc(sizeof(*dummy));//假节点struct ListNode* prev = dummy;while (l1 && l2) {if (l1->val < l2->val) {prev->next = l1;l1 = l1->next;} else {prev->next = l2;l2 = l2->next;}prev = prev->next;}prev->next = (l1 == NULL) ? l2 : l1;return dummy->next;}