摘要：
题意： Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If the number of nodes is not a multiple of k th 阅读全文
摘要：
题意： 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. Yo 阅读全文