天行健，君子以自强不息

Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space? 题解：判断一个单链表是不是回文串，可以将后半部分进行反转。注意这里找中间位置可以用两指针的方法，设置快慢指针，快指针是慢指针两倍速度从而快指针到结尾时可以保证慢

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 题解：复制一个随机链表，本题复制时先用map标记原地址到复制地址的映...

  Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. 题解：给定一个链表有序的转成平衡BST，关键这里我用额外空间MLE所以应该在链表上直接进行，最优化的应该是设计两个指针，一个slow一个fast用来遍历中间节点，然后左右子...

Reverse a linked list from position m to n. Do it in one-pass. Note: 1 ≤ m ≤ n ≤ length of list. Example: Input: 1->2->3->4->5->NULL, m = 2, n = 4 Output: 1->4->3->2->5-...

Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x. You should preserve the original relative order of the nodes in each of t...