摘要：Linked List CycleGiven a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?算法思路1：快慢指针，当两个指针相遇，则表示有环，... 阅读全文

摘要：Palindrome NumberDetermine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers b... 阅读全文

摘要：Reverse IntegerReverse digits of an integer.Example1:x = 123, return 321Example2:x = -123, return -321click to show spoilers.Have you thought about th... 阅读全文

摘要：Plus OneGiven a non-negative number represented as an array of digits, plus one to the number.The digits are stored such that the most significant dig... 阅读全文

摘要：Set Matrix ZeroesGiven amxnmatrix, if an element is 0, set its entire row and column to 0. Do it in place.Follow up:Did you use extra space?A straight... 阅读全文

摘要：Validate Binary Search TreeRecover Binary Search TreeSymmetric TreeSame TreeMaximum Depth of Binary TreeConstruct Binary Tree from Preorder and Inorde... 阅读全文

摘要：Count and SayThe count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ...1is read off as"one 1"or11.11is r... 阅读全文

摘要：Palindrome PartitioningGiven a strings, partitionssuch that every substring of the partition is a palindrome.Return all possible palindrome partitioni... 阅读全文

摘要：Letter Combinations of a Phone NumberGiven a digit string, return all possible letter combinations that the number could represent.A mapping of digit ... 阅读全文

摘要：Restore IP AddressesGiven a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given"255255... 阅读全文

摘要：Generate ParenthesesGivennpairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, givenn= 3, a sol... 阅读全文

摘要：Word SearchGiven a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, wh... 阅读全文

摘要：N-Queens IIFollow up for N-Queens problem.Now, instead outputting board configurations, return the total number of distinct solutions.算法思路：与[leetcode]... 阅读全文

摘要：N-QueensThen-queens puzzle is the problem of placingnqueens on ann×nchessboard such that no two queens attack each other.Given an integern, return all... 阅读全文

摘要：Combination SumGiven a set of candidate numbers (C) and a target number (T), find all unique combinations inCwhere the candidate numbers sums toT.Thes... 阅读全文

摘要：Combination Sum IIGiven a collection of candidate numbers (C) and a target number (T), find all unique combinations inCwhere the candidate numbers sum... 阅读全文