brenda_zhao-优快云博客

原创 Medium 285题 Inorder Successor in BST

Question:Given a binary search tree and a node in it, find the in-order successor of that node in the BST.Solution:分两种情况讨论，参考了https://segmentfault.com/a/1190000003792039，存下所有路径/** * Defin

2016-11-02 13:22:20 368

原创 Medium 186题 Reverse Words in a String II

Question:Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters.The input string does not contain leading or trailing spaces and the word

2016-11-02 07:08:49 333

原创 Easy 252题 Meeting Rooms

Question:Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (si i), determine if a person could attend all meetings.For example,Given [[0, 30],[

2016-10-29 02:26:32 287

原创 Hard 65题 Valid Number

Question:Validate if a given string is numeric.Some examples:"0" => true" 0.1 " => true"abc" => false"1 a" => false"2e10" => trueNote: It is intended for the problem statemen

2016-10-27 11:21:35 317

原创 Hard 297题 Serialize and Deserialize Binary Tree

Question:Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connec

2016-10-27 02:43:40 221

原创 Medium 47题 Permutations II

Question:Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2] have the following unique permutations:[ [1,1,2],

2016-10-26 10:52:51 199

原创 Medium 46题 Permutations

Question:Given a collection of distinct numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3

2016-10-26 10:46:34 240

原创 Medium 311题 Sparse Matrix Multiplication

Question:Given two sparse matrices A and B, return the result of AB.You may assume that A's column number is equal to B's row number.Example:A = [ [ 1, 0, 0], [-1, 0, 3]]B = [

2016-10-26 08:34:39 247

原创 Easy 13题 Roman to Integer

Question:Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.Solution:public class Solution { public int romanToInt(String s) {

2016-10-26 08:20:54 187

原创 Easy 237题 Delete Node in a Linked List

Question: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

2016-10-26 03:12:06 207

原创 Easy 9题 Palindrome Number

Question:Determine whether an integer is a palindrome. Do this without extra space.Solution:调试半天。。。但居然过了61%public class Solution { public boolean isPalindrome(int x) { if(x<0)

2016-10-25 12:37:45 187

原创 Easy 8题 String to Integer (atoi)

Question:Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the po

2016-10-25 07:18:45 206

原创 Medium 277题 Find the Celebrity

Question:Suppose you are at a party with n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. The definition of a celebrity is that all the other n - 1 people kn

2016-10-25 06:10:54 206

原创 Easy 101题 Symmetric Tree

Question:Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree [1,2,2,3,4,4,3] is symmetric: 1 / \ 2 2 / \

2016-10-25 04:10:37 200

原创 Medium 366题 Find Leaves of Binary Tree

Question:Given a binary tree, collect a tree's nodes as if you were doing this: Collect and remove all leaves, repeat until the tree is empty.Example:Given binary tree 1

2016-10-25 01:03:26 200

原创 Medium 254题 Factor Combinations

Question:Numbers can be regarded as product of its factors. For example,8 = 2 x 2 x 2; = 2 x 4.Write a function that takes an integer n and return all possible combinations of its facto

2016-10-24 15:31:38 287

原创 Medium 256题 Paint House

Question:There are a row of n houses, each house can be painted with one of the three colors: red, blue or green. The cost of painting each house with a certain color is different. You have to p

2016-10-24 12:43:09 192

原创 Medium 5题 Longest Palindromic Substring

Question:Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.Solut

2016-10-24 11:59:23 188

原创 Hard 68题 Text Justification

Question:Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.You should pack your words in a greedy a

2016-10-24 01:37:36 188

原创 Medium 364题 Nested List Weight Sum II

Question:Given a nested list of integers, return the sum of all integers in the list weighted by their depth.Each element is either an integer, or a list -- whose elements may also be intege

2016-10-22 02:09:53 217

原创 Medium 244题 Shortest Word Distance II Medium 245题 Shortest Word Distance III

Medium 244题 Shortest Word Distance II Question:This is a follow up of Shortest Word Distance. The only difference is now you are given the list of words and your method will be calledrepeate

2016-10-21 12:20:47 292

原创 Easy 243题 Shortest Word Distance

Question:Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list.For example,Assume that words = ["practice", "makes", "perfec

2016-10-21 08:57:00 181

原创 Easy 339题 Nested List Weight S

Question:Solution:DFS:/** * // This is the interface that allows for creating nested lists. * // You should not implement it, or speculate about its implementation * public interface Nest

2016-10-20 11:35:00 413

原创 Easy 170题 Two Sum III - Data structure design

Question:Design and implement a TwoSum class. It should support the following operations: add and find.add - Add the number to an internal data structure.find - Find if there exist

2016-10-20 06:04:41 349

原创 Easy 205题 Isomorphic Strings

Question:Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be rep

2016-10-20 05:02:09 311

原创 Medium 213题 House Robber II

Question:After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time, all houses at this place are a

2016-10-20 04:05:36 218

原创 Easy 198题 House Robber

Question:You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that

2016-10-19 13:39:53 171

原创 Easy 155题 Min Stack

Question:Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) -- Push element x onto stack.pop() -- Removes the element on top of the stac

2016-10-18 22:55:45 160

原创 Easy 7题 Reverse Integer

Question:Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321Solution:用long处理溢出，注意long和int不能相加~我的笨办法public class Solution { public int re

2016-10-18 13:31:28 204

原创 Easy 6题 ZigZag Conversion

Question: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 for better legibility)P A H

2016-10-18 12:10:10 184

原创 Medium 151题 Reverse Words in a String

Question:Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".Solution:String[] parts = s.trim().split("\\s+");S

2016-10-18 10:40:51 288

原创 Hard 146题 LRU Cache

Question:Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.get(key) - Get the value (will always be positive)

2016-10-17 12:20:57 204

原创 Hard 76题 Minimum Window Substring

Question:Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).For example,S = "ADOBECODEBANC"T = "ABC"Minimum

2016-10-12 00:17:11 246

原创 Hard 10题 Regular Expression Matching

Question:Implement regular expression matching with support for '.' and '*'.'.' Matches any single character.'*' Matches zero or more of the preceding element.The matching should cover the

2016-10-11 22:53:31 240

原创 Hard 301题 Remove Invalid Parentheses

Question:Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results.Note: The input string may contain letters other than the paren

2016-10-11 09:26:03 192

原创 Medium 314题 Binary Tree Vertical Order Traversal

Question:Given a binary tree, return the vertical order traversal of its nodes' values. (ie, from top to bottom, column by column).If two nodes are in the same row and column, the order shou

2016-10-11 09:24:50 235

原创 Medium 98题 Validate Binary Search Tree

Question：Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keys less than th

2016-10-11 07:56:16 147

原创 Easy 157题 Read N Characters Given Read4

Question:The API: int read4(char *buf) reads 4 characters at a time from a file.The return value is the actual number of characters read. For example, it returns 3 if there is only 3 charact

2016-10-11 05:59:47 156

原创 Easy 257题 Binary Tree Paths

Question:Given a binary tree, return all root-to-leaf paths.For example, given the following binary tree: 1 / \2 3 \ 5All root-to-leaf paths are:["1->2->5", "1-

2016-10-11 04:38:59 194

原创 Easy 278题 First Bad Version

Question:You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is develop

2016-10-11 03:42:29 157

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