ljffdream的专栏

【题目】Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.【思路】这道题目就和array不一样，因为是linkedlist所以，不能随意访问到中间的元素，那么就只能一步一步从头开始顺序访问，从列表到BST,我们能感受到构

【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】Merge k sorted Linked Lists and return it as one sorted lists. Analyze and describe its complexity .【思路】leetcode clean book【代码】 private static final Comparator listComparator = new

【题目】Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between tw

【题目】【思路】First of all, allow me to explain the meaning of strict O(1) auxiliary space complexity.It means the maximum number of memory used by the program, except the memory taken by th

【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]Given two words (beginWord and endWord), and a dictionary, find the length ofshortest transformation sequence frombeginWord to endWord, such that:Only one letter can be changed at a ti

【题目】Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node

【题目】 Reverse a singly linked list.click to show more hints.Hint: A linked list can be reversed either iteratively or recursively. Could you implement both?【思路】 我自己想的办法就是可以用一个stack，先把每一个元素都装进去

[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】：Write a program to find the node at which the intersection of two singly linked lists begins.For example, the following two linked lists:A: a1 → a2 ↘

Write a program to find the node at which the intersection of two singly linked lists begins.For example, the following two linked lists:A: a1 → a2 ↘

【题目】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

【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

【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