摘要：Permutations IIGiven a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2]have the follow... 阅读全文

摘要：PermutationsGiven a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3]... 阅读全文

摘要：CombinationsGiven two integersnandk, return all possible combinations ofknumbers out of 1 ...n.For example,Ifn= 4 andk= 2, a solution is:[ [2,4], [3... 阅读全文

摘要：这篇博文较长，且理论为主，因为我准备换种风格，以保证大家看的时候不会觉得无聊，看完如果对dfs还是一头雾水，那我也不会请你吃麻辣烫开场:刷了一遍leetcode，发现DFS是个特别强大，且出题率特别高的一个基础算法，第一次接触DFS是树的一个搜索算法，相对而言的是BFS。根据难度与考察频率参考表的建... 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