Given a singly linked list L: L0→L1→…→Ln-1→Ln,reorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→… You must do this in-place without altering the nodes' values. For example,Given {1,2,3,4}, reorder it to {1,4,2,3}. 解题思路: 设置一个指针mid指向链表的中间结点: 将mid之后的半个链表进行反转,反转后的链表i…