摘要：Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given"25525511135",return["255.2... 阅读全文

摘要：Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.分析：首先我们熟悉下Roman数字组成规则：罗马数字一共有7个符号，'I':1, 'V'... 阅读全文

摘要：Given a strings1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation... 阅读全文

摘要：Given an absolute path for a file (Unix-style), simplify it.For example,path="/home/", =>"/home"path="/a/./b/../../c/", =>"/c"click to show corner cas... 阅读全文

摘要：Implementatoito convert a string to an integer.Hint:Carefully consider all possible input cases. If you want a challenge, please do not see below and ... 阅读全文

摘要：Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.For example,"A man, a plan, a canal: Pana... 阅读全文

摘要：Given a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid.The brackets must close in the correct ... 阅读全文

摘要：The string"PAYPALISHIRING"is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font fo... 阅读全文

摘要：Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.分析：我们比较熟悉由一个sorted array生成一个BST，不同的是这里的数据... 阅读全文

摘要：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 ... 阅读全文

摘要：Sort a linked list using insertion sort.分析：insertion sort是将当前元素插入到已经排好序的元素的适当位置，时间复杂度为O(n^2)。class Solution {public: ListNode *insertionSortList(Li... 阅读全文

摘要：Given a linked list, return the node where the cycle begins. If there is no cycle, returnnull.Follow up:Can you solve it without using extra space?分析：... 阅读全文

摘要：Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?分析：如果一个linked list中有环，那么在用一个快指针和一个慢指针遍历该li... 阅读全文

摘要：Mergeksorted linked lists and return it as one sorted list. Analyze and describe its complexity.分析：一个很简单的解法是调用k-1次merge two sorted linkedlist，假设每个list... 阅读全文

摘要：Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.代码：class ... 阅读全文

摘要：Given a linked list and a valuex, partition it such that all nodes less thanxcome before nodes greater than or equal tox.You should preserve the origi... 阅读全文

摘要：Given a sorted linked list, delete all nodes that have duplicate numbers, leaving onlydistinctnumbers from the original list.For example,Given1->2->3-... 阅读全文

摘要：Given a linked list, remove thenthnode from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. After re... 阅读全文

摘要：Given a singly linked listL: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 exam... 阅读全文

摘要：Reverse a linked list from positionmton. Do it in-place and in one-pass.For example:Given1->2->3->4->5->NULL,m= 2 andn= 4,return1->4->3->2->5->NULL.No... 阅读全文