七年之后

摘要： Given a linked list, swap every two adjacent nodes and return its head.For example, Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. You may not modify the values in the list, only nodes itself can be changed.思考：考虑几种情况：空链表，单节 阅读全文

摘要： Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.思考：合并双链表的基础上增加循环。/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public: ListNode *... 阅读全文