ljffdream的专栏

【题目】Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?【分析】使用two pointer的思想，因为如果一个list存在环的话，那个两个pointer必定会相遇！~经过各种改进之后！~写出的

[timu]Follow up for "Remove Duplicates":What if duplicates are allowed at most twice?For example,Given sorted array nums = [1,1,1,2,2,3],Your function should return length = 5, with

【题目】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

【题目】Given a list, rotate the list to the right by k places, where k is non-negative.For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL.【思路】实质就是n-k个元素挪到了链子的前面， 第

【题目】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?【思路】panlidrome的话，回文，就是前后是一样的。第一个和最后一个一样， 第二个和倒数第二个一样。linked list

【题目】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

[题目]Remove all elements from a linked list of integers that have value val.ExampleGiven: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6Return: 1 --> 2 --> 3 --> 4 --> 5Credits:Special th

【题目】Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and

【题目】Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue.Here, we will use the

[timu] Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adja