Blog Archive 2017 [Question] Trie Wildcard String Matching May 22 2017 [Question] Dutch National Flag Problem May 13 2017 2016 [Design] How to Design Logging Aug 01 2016 [Design] MVC, MVP and MVVM Jul 31 2016 [Design] Design Twitter Jul 11 2016 [Octopress] Add Aside Content to Octopress Jun 11 2016 [Design] User Registry Table Design May 08 2016 2015 [Design] Designing a Simple Web Crawler Nov 22 2015 [Question] Swizzle Sort Nov 21 2015 [Design] How to Generate Maze Nov 21 2015 [Design] Strategy Design Pattern Nov 18 2015 [Question] Partition Problem (Divide Array Into Halves) Nov 15 2015 [LeetCode 188] Best Time to Buy and Sell Stock IV Nov 04 2015 [Java OOP] Java ArrayList Implementation Oct 28 2015 [Java OOP] Static Class and Inner Class Oct 23 2015 [Java OOP] What Is Java Exception Oct 23 2015 [Java OOP] Java Vector and ArrayList Oct 23 2015 [Java OOP] Template Method Pattern (Abstract Class) Oct 23 2015 [Fundamental] Reflexive, Symmetric and Transitive Rules Oct 22 2015 [Fundamental] Polynomial, Quadratic, Cubic and Exponential Oct 22 2015 [Fundamental] What Is a Literal? Oct 22 2015 [Java OOP] Why Avoid Using Protected? Oct 22 2015 [Fundamental] UML Class Diagrams Oct 14 2015 [LintCode] Segment Tree Query II Oct 13 2015 [LintCode] Segment Tree Query Oct 13 2015 [LintCode] Segment Tree Modify Oct 13 2015 [LintCode] Segment Tree Build II Oct 13 2015 [LintCode] Segment Tree Build Oct 13 2015 [Fundamental] Segment Tree Oct 08 2015 [Question] Largest Sub-square With Edges Filled Oct 07 2015 [Question] Find Cloest Leaf in Binary Tree Oct 07 2015 [Amazon] All Strings by Placing Spaces Oct 07 2015 [Fundamental] the 7 Bridges Problem Oct 04 2015 [Google] Shortest Manhattan Distance Oct 02 2015 [Design] Facebook Photo Storage Sep 02 2015 [Design] How Google Search Works Aug 30 2015 [NineChap System Design] Class 4.2: Search Engine Aug 30 2015 [NineChap System Design] Class 4.1: Crawler Aug 30 2015 [NineChap System Design] Class 3.2: Web Service Aug 28 2015 [NineChap System Design] Class 3.1: Web Service Aug 28 2015 [NineChap System Design] Class 2.2: Database Aug 26 2015 [NineChap System Design] Class 2.1: Database Aug 26 2015 [Java OOP] Three Properties of Class/Object Aug 24 2015 [NineChap System Design] Class 1.3: Improvement Aug 23 2015 [NineChap System Design] Class 1.2: An Example Aug 23 2015 [NineChap System Design] Class 1.1: Overview Aug 23 2015 [Design] How Is Pipe Implemented in Unix/Linux Jul 23 2015 [Design] Cryptographic Standard, AES and RSA Jun 09 2015 [Design] Linux and TCP Ports Jun 08 2015 [Java OOP] Overload, Override, Compile, Runtime (Static/Dynamic Polymph) May 24 2015 [Palantir] Sort Letters Given Lexicographic Order May 21 2015 [LeetCode 189] Rotate Array May 10 2015 [LeetCode 190] Reverse Bits May 10 2015 [LeetCode 200] Number of Islands May 10 2015 [LeetCode 191] Number of 1 Bits May 10 2015 [LeetCode 198] House Robber May 10 2015 [LeetCode 201] Bitwise and of Numbers Range May 10 2015 [LeetCode 199] Binary Tree Right Side View May 10 2015 [LeetCode 187] Repeated DNA Sequences May 01 2015 [LeetCode 179] Largest Number Apr 15 2015 [LeetCode 174] Dungeon Game Apr 15 2015 [LeetCode 173] Binary Search Tree Iterator Apr 15 2015 [UVa] Wooden Sticks Apr 14 2015 [Question] 编程之美 NIM 一排石头的游戏 Apr 14 2015 [LeetCode 169] Majority Element Apr 14 2015 [LeetCode 168] Excel Sheet Column Title Apr 14 2015 [LeetCode 164] Maximum Gap Apr 13 2015 [LeetCode 172] Factorial Trailing Zeroes Apr 13 2015 [LeetCode 171] Excel Sheet Column Number Apr 13 2015 [Palantir] MultiMap in Java Without Using Collections Apr 12 2015 [Palantir] Find Duplicate Within K Distance Apr 12 2015 [LeetCode 162] Find Peak Element Apr 12 2015 [LeetCode 165] Compare Version Numbers Apr 12 2015 [LeetCode 166] Fraction to Recurring Decimal Apr 11 2015 [LeetCode 160] Intersection of Two Linked Lists Apr 08 2015 [Octopress] Add Google AdSense to Octopress Apr 07 2015 [LeetCode 155] Min Stack Apr 07 2015 [LeetCode 152] Maximum Product Subarray Apr 07 2015 [LeetCode 154] Find Minimum in Rotated Sorted Array II Apr 07 2015 [LeetCode 153] Find Minimum in Rotated Sorted Array Apr 07 2015 [Design] HBase and HDFS Feb 15 2015 [Design] Speed Up Webpage for Slow Connection (4) Feb 14 2015 [Design] Speed Up Webpage for Slow Connection (3) Feb 14 2015 [Design] Speed Up Webpage for Slow Connection (2) Feb 14 2015 [Design] Speed Up Webpage for Slow Connection (1) Feb 14 2015 [LinkedIn] Sort Part to Make Entire Array Sorted Feb 13 2015 [Google] Minimum Adjustments Feb 13 2015 [LinkedIn] Unique Combination of Factors (因式分解) Feb 13 2015 [LinkedIn] Sum of Integer Weighted by Depth Feb 13 2015 [LinkedIn] Executive's Schedule Feb 12 2015 [LinkedIn] Isomorphic Strings Feb 11 2015 [Design] Application Server vs. Web Server Feb 11 2015 [Design] Design Cache System (`) Feb 10 2015 [Google] Number of Slices Feb 09 2015 [Design] Intro to Google Spanner Feb 09 2015 [Google] Heap and BST Conversion Feb 09 2015 [Question] Count Multiples of Array Feb 09 2015 [Google] Array Signature Feb 09 2015 [Java OOP] Can Abstract Class Have 0 Abstract Method? Feb 09 2015 [Java OOP] Can Abstract Class Have Constructor Feb 09 2015 [Google] Transform a Unbalanced Tree Into Balanced Tree Feb 08 2015 [Google] Transform a Unbalanced Tree Into Balanced Tree Feb 08 2015 [Facebook] Generate Number With Given Probability Feb 08 2015 [Design] Find Similar Library Books Feb 08 2015 [Design] Difference: Internet and the Web Feb 08 2015 [Google] BST Find Ceiling Feb 08 2015 [Design] Big Data - Find Common Elements in 2 Lists Feb 08 2015 [Question] Reservoir Sampling Feb 07 2015 [Design] Multithreading Async Increment Problem Feb 07 2015 [Google] Max Prodcut of Strings That Have No Common Char Feb 07 2015 [Google] First Unique URL Feb 07 2015 [Google] Continental Divider Feb 07 2015 [Question] Check String With No Common Letters (Bitmask) Feb 07 2015 [Design] Winning Games Rank (Pagerank) Feb 05 2015 [Google] Set Cover Problem Feb 05 2015 [Java OOP] PubSub (Publish–subscribe) Pattern Feb 05 2015 [Google] Multi-server Messaging System Feb 05 2015 [Google] Implement a Blocking Queue Feb 05 2015 [Google] Snakes and Ladders Feb 04 2015 [Google] Number of Subtrees With Even Nodes Feb 04 2015 [Amazon] Grep Command Interview Question Feb 04 2015 [Google] Data Structure of Insert, Remove, GetRandom Feb 04 2015 [Google] Collatz Conjecture (Oneness Property) Feb 04 2015 [Design] Monitor Rps for Past Sec/min/hr Feb 03 2015 [Question] Stock Span Problem (Couting BST) Feb 01 2015 [Design] Limit the Request Per Second Feb 01 2015 [Greedy] Each Employee 2 Events Feb 01 2015 [Greedy] Activity Selection Problem Feb 01 2015 [Question] 2D Bin Packing Jan 30 2015 [Question] Product Array Puzzle Jan 29 2015 [Apple] Calculate Area Jan 29 2015 [Question] Packing Rectangles Jan 29 2015 [Question] Two Dimensional Knapsack Problem Jan 28 2015 [Fundamental] Implement Trie and Suffix Tree Jan 28 2015 [Fundamental] Suffix Tree Jan 27 2015 [Fundamental] Suffix Array Jan 27 2015 [Fundamental] Prefix Tree Jan 27 2015 [Fundamental] Pattern Searching Algorithms Jan 27 2015 [Google] Generate Request ID Jan 27 2015 [Google] Make a Java Method Thread-safe Jan 26 2015 [Question] Push and Pop Sequences of Stacks Jan 26 2015 [Design] Distributed Caching - Memcached Jan 24 2015 [Design] Design Google Suggest (Autocomplete) Jan 24 2015 [Google] Top N Values From Sum of 2 Arrays Jan 20 2015 [Java OOP] Java Vector and ArrayList Jan 20 2015 [Java OOP] Interface and Abstract Classes Jan 20 2015 [Design] Difference Between HTTP and HTTPS Jan 20 2015 [Palantir] Largest Basin Size in Matrix Jan 20 2015 [Design] Difference Between HTTP Protocol and TCP Protocol Jan 19 2015 [Question] Check if Given Point Inside Polygon Jan 19 2015 [Question] Check if Two Line Segments Intersect Jan 19 2015 [Question] Maximum Square Sub-matrix With All 1s Jan 18 2015 [Google] Lexicographic Order (Letter Replacement) of Dictionary Jan 18 2015 [Amazon] Lexicographic Rank of a String Jan 18 2015 [Amazon] Find Nodes of Distance K From Binary Tree Jan 17 2015 [Java OOP] Java BlockingQueue (2) Jan 12 2015 [Java OOP] Java BlockingQueue (1) Jan 12 2015 [Java OOP] BlockingQueue and Thread Pool Jan 12 2015 [Question] Number of Occurence of Given Sub-sequence Jan 11 2015 [Question] Number of Distinct Sub-sequence Jan 11 2015 [Amazon] Longest Repeating Substring Jan 11 2015 [Google] Crazy Distance Between Strings Jan 11 2015 [Google] Check if Repeating Subsequence Exists Jan 11 2015 [LinkedIn] Find All Repeating Substring With Given Length Jan 11 2015 [Question] All Distinct Subsequences With Given Length Jan 11 2015 [Google] Diameter of a Binary Tree Jan 11 2015 [Google] Reverse a Stack Without DS Jan 10 2015 [Amazon] Mininum Range That Includes at Least One Jan 10 2015 [Google] Maximum Count Array in a Queue Jan 10 2015 [Google] Form a Queue Given Heights Jan 10 2015 [Design] Terminology: N-gram Jan 09 2015 [Question] Most Frequent Word From a Book Jan 09 2015 [Amazon] Match Triplet With Reverse Order Jan 09 2015 [Design] Big Data - Top K Frequency (Hands-on) Jan 09 2015 [Design] Real Time Top K Jan 09 2015 [Google] Number of Distinct Substrings Jan 08 2015 [Google] Check All Numbers Given the Decimal Scale Jan 08 2015 [Facebook] Scheduling Jobs With Max Cost Jan 07 2015 [Question] Longest Common Substring Jan 07 2015 [Design] P2P Technology Jan 07 2015 [Design] Distributed Hash Table Jan 06 2015 [Design] Cloud, Grid and Cluster Jan 06 2015 [Design] Big Data Storage Jan 06 2015 [Facebook] Write a Json Prettifier Jan 06 2015 [Question] Frog Crossing (Dynamic Programming) Jan 02 2015 2014 [Design] Database Indexing Dec 27 2014 [Java OOP] Java Runtime Exception Dec 23 2014 [Ruby] Endless Error With Gem Dependencies Dec 23 2014 [Java OOP] Override/overload Java Main Method Dec 22 2014 [Java OOP] Common Root of Java Classes Dec 22 2014 [Java OOP] Interface Extend Another Interface Dec 22 2014 [Question] Split an Integer or Coin Dec 22 2014 [Ruby] RubyGems, Gem, Gemfile and Bundler Dec 22 2014 [Facebook] Maximum Sum Such That No Two Elements Are Adjacent Dec 22 2014 [Java OOP] Discussion of Polymorphism Dec 22 2014 [Facebook] Binary Search Tree 3Sum Dec 18 2014 [Question] Equilibrium Points in 2D Array Dec 17 2014 [Facebook] Print a Binary Tree in Vertical Order Dec 17 2014 [Epic] Patient Disease Data Structure Dec 08 2014 [Question] Axis Aligned Rectangles Dec 02 2014 [Question] Multiples of 3 and 5 Nov 30 2014 [Google] Code a HashMap Nov 04 2014 [Question] Find Row With Most 1s Nov 01 2014 [Question] Interleave Positive and Negative Numbers Oct 08 2014 [CC150v5] 18.7 Longest Word Made From Other Words Oct 02 2014 [CC150v5] 17.14 Optimal Way to Unconcatenate Doc Oct 01 2014 [CC150v5] 17.13 Convert BST to DLL Sep 30 2014 [CC150v5] 11.8 Get Rank in Stream of Integers Sep 28 2014 [CC150v5] 17.6 Order an Array by Sorting Middle Sep 27 2014 [CC150v5] 14.6 Implement CircularArray in Java Sep 26 2014 [CC150v5] 12.0 Example - Troubleshoot Google Chrome Sep 24 2014 [CC150v5] 11.4 Sort 20GB File Sep 24 2014 [CC150v5] 9.10 Stack Up the Boxes Sep 17 2014 [CC150v5] 9.11 Parenthesize the Expression Sep 17 2014 [CC150v5] 9.7 Paint Fill in Map Sep 17 2014 [CC150v5] 9.3 Find Magic Index Sep 17 2014 [CC150v5] 5.6 Swap Odd and Even Bits Sep 16 2014 [Google] Guess Password Sep 16 2014 [CC150v5] 5.5 Calculate Bits Conversion Required Sep 16 2014 [Brain Teaser] 6.1 Bottles of Pills Sep 16 2014 [CC150v5] 5.1 Binary Merge 2 Numbers Sep 16 2014 [CC150v5] 3.7 Stack of Animals Sep 15 2014 [CC150v5] 3.2 Stack Min Value Sep 15 2014 [CC150v5] 2.7 Linked List Palindrome Sep 15 2014 [CC150v5] 3.0 Example - Implement Stack Sep 15 2014 [CC150v5] 2.2 Kth Last Element (Recursive) Sep 14 2014 [Design] DNS Communication Protocol Sep 12 2014 [Question] Celebrity Problem Sep 11 2014 [Google] Barrier, Goods Van and Distance Sep 11 2014 [Google] Arithmetic Progression Triplet Sep 11 2014 [Google] Length of Longest Arithmetic Progression (LLAP) Sep 11 2014 [CC150v4] 20.6 Top Million From Billion Sep 10 2014 [CC150v4] 20.12 Sub-matrix With Largest Sum Sep 10 2014 [CC150v4] 20.3 Generate M Int From Array of Size N Sep 10 2014 [CC150v4] 20.8 Full Text Search (Suffix Tree) Sep 10 2014 [CC150v4] 20.11 Find Subsquare With Black Border Sep 10 2014 [CC150v4] 20.4 Count 2s in Digits Sep 10 2014 [CC150v4] 19.4 Get Max Number Without Comparator Sep 09 2014 [CC150v4] 19.6 Convert Integer to English Sep 09 2014 [Google] Winner of Tic-tac-toe Sep 09 2014 [CC150v4] 11.4 Test Webpage Without Tools Sep 08 2014 [CC150v4] 15.2 SQL Types of Join Sep 08 2014 [CC150v4] 15.1 SQL Count and Group by Statement Sep 08 2014 [CC150v4] 11.2 Random Error Debugging 2 Sep 08 2014 [CC150v4] 14.5 Java Reflection Sep 08 2014 [CC150v4] 14.1 Java Private Constructor Sep 08 2014 [CC150v4] 14.6 Java HashMap Counter Sep 08 2014 [CC150v4] 14.2 Java Finally Statement Sep 08 2014 [CC150v4] 14.3 Java Final, Finally and Finalize Sep 08 2014 [CC150v4] 10.4 Implement Mathematical Operators Sep 08 2014 [CC150v4] 10.6 Find Collinear in 2D Plane Sep 08 2014 [CC150v4] 9.0 Example - Sort Persons Sep 07 2014 [CC150v4] 9.5 Search Array Containing Empty String Sep 07 2014 [CC150v4] 8.4 Generate Permutation Recursively Sep 07 2014 [CC150v4] 5.7 Find Missing Number Sep 07 2014 [Brain Teaser] 6.2 Cover the Chess Board Sep 07 2014 [CC150v4] 5.2 Convert Integer to Binary Form Sep 07 2014 [CC150v4] 3.6 Sort Stack Sep 06 2014 [CC150v4] 4.8 Print Path Sum to Value Sep 06 2014 [CC150v4] 3.4 Towers of Hanoi Sep 06 2014 [CC150v4] 4.5 Find Next Node in BST Sep 06 2014 [CC150v4] 4.7 Check Subtree Sep 06 2014 [Google] Form a Palindrome With Insertion Sep 06 2014 [Google] Unsolved Mystery of UTF8 Encoding Sep 04 2014 [Google] Find Second Shortest Path Sep 04 2014 [Google] Weird Sort Array Sep 03 2014 [Google] String Replacement Question Sep 03 2014 [Design] Leader Election Sep 03 2014 [Java OOP] Observer Pattern Sep 02 2014 [Google] Find Anagrams in Dictionary Sep 02 2014 [Google] Array Distance A(i)+A(j)+(j-i) Sep 02 2014 [Design] Multithreading - Deadlock Prevention Sep 01 2014 [Facebook] Hamming Distance of Array Sep 01 2014 [Google] Crosswod Solver Sep 01 2014 [Fundamental] Travelling Salesman Problem Aug 30 2014 [Fundamental] Min-Max Algorithm (Minmax) Aug 30 2014 [Design] Cryptographic Hash, MD5 and Digital Signature Aug 30 2014 [Fundamental] A-Star Search Aug 30 2014 [Google] Boggle Solver (Search Words From Matrix) Aug 29 2014 [CC150v4] 10.7 Ugly Numbers (Hamming Numbers) Aug 28 2014 [Google] Google Pre-interview Coaching Aug 28 2014 [Design] HTTP Cookie Aug 28 2014 [Twitter] Largest Cycle in Permutation Aug 27 2014 [Google] Google API Read4096 (read4K) Aug 27 2014 [Question] Duplicate Rows in Matrix Aug 27 2014 [Twitter] Count Visible Nodes in Binary Tree Aug 27 2014 [Design] Virtual Memory, Page Fault and Thrashing Aug 26 2014 [Testing] Test hashCode() Function Aug 26 2014 [Design] OOD Design of Elevator Aug 26 2014 [CC150v5] 8.4 Design a Parking Lot Aug 25 2014 [CC150v5] 8.9 Design a In-memory File System Aug 25 2014 [CC150v5] 8.10 Implement a Hashmap Aug 25 2014 [CC150v5] 8.8 Design Othello Game Aug 24 2014 [CC150v5] 8.7 Design Online Chat Server (2) Aug 24 2014 [CC150v5] 8.7 Design Online Chat Server (1) Aug 24 2014 [Design] Stack and Heap Aug 23 2014 [Design] Shared Hosting vs. VPS Hosting Aug 23 2014 [Design] Merits of BST Over HashTables Aug 23 2014 [CC150v5] 8.1 Design a Generic Deck of Cards Aug 22 2014 [Java OOP] Singleton, 3 Implementations Aug 20 2014 [Question] Square Count of Matchstick Graph Aug 20 2014 [Question] Ways of Dice Throw Aug 20 2014 [Question] Count Set Bit in Binary Number Aug 20 2014 [Java OOP] Singleton Pattern Introduction Aug 19 2014 [Java OOP] Factory Pattern Aug 19 2014 [Question] Count Level in Perfect Binary Tree Aug 19 2014 [ItInt5] Numbers Concatenation Max (Largest Number) Aug 17 2014 [ItInt5] Number of Valid Trees Given Preorder and Postorder Aug 17 2014 [Twitter] Arithmetic Expression Evaluation Aug 17 2014 [Google] Orthogonal Traverse the Map (`) Aug 16 2014 [ItInt5] Excel Decimal Conversion Aug 16 2014 [Facebook] Task Scheduling Question Aug 15 2014 [Google] Product All 1s Aug 15 2014 [ItInt5] 跳马问题加强版 Aug 15 2014 [Question] Greatest Common Divisor Aug 15 2014 [Google] Alphabet Table (`) Aug 15 2014 [Facebook] Query Search (HashMap, Suffix Array) Aug 14 2014 [CC150v4] 9.7 Circus Tower Routine Aug 12 2014 [Design] From Client/Server to Multi-Tier Aug 12 2014 [ItInt5] Maximum Circular Subarray Sum Aug 11 2014 [Design] TCP 3-Way Handshake Aug 11 2014 [Google] Count Complete Binary Tree Aug 11 2014 [Design] Big Data - Fuzzy Search Url (Bloom Filter) Aug 10 2014 [Design] Big Data - Find Median Numbers Aug 10 2014 [Design] Big Data - Find Existence of a Number Aug 10 2014 [Design] Big Data - Top K Frequency (Case Analysis) Aug 10 2014 [Design] Big Data - Remove Duplicate Numbers Aug 10 2014 [Testing] Test Command Line Copy Aug 09 2014 [Design] Process vs. Thread Aug 09 2014 [Design] Median of Array in Distributed Computers Aug 09 2014 [Design] Functional Programming Aug 09 2014 [Java OOP] Thread Pool Pattern Aug 08 2014 [Design] Producer Consumer Problem Aug 08 2014 [Question] Max Sum of Non-Consecutive Elements Aug 08 2014 [Question] Decimal to Hexadecimal Aug 08 2014 [Design] Composition Over Inheritance Aug 08 2014 [Question] Add Integers Without +/++ Aug 08 2014 [CC150v4] 9.4 Sort Large Files Aug 07 2014 [Testing] Random Error Debugging 1 Aug 07 2014 [Google] Million Phone Numbers Aug 07 2014 [Design] Distributed Network Bottleneck Aug 07 2014 [Google] Postorder Successor in Binary Tree Aug 06 2014 [Design] Networks and TCP/IP Aug 06 2014 [Design] HTTP Headers Aug 06 2014 [Google] Connect Graph Nodes and Avoid Intersect Aug 06 2014 [Question] Print Numbers Containing 5 Aug 05 2014 [Google] Write a Random Number Generator Aug 05 2014 [Java OOP] Upcasting, Downcasting and Object Slicing Aug 05 2014 [Google] Replace Question Mark With Number Aug 05 2014 [Design] MapReduce Intro Aug 05 2014 [Design] MapReduce Common Friends Example Aug 05 2014 [Design] Amazon Web Services Aug 05 2014 [Google] Traveller Path Problem Aug 04 2014 [Design] Overview of Big Data Technology Aug 04 2014 [Design] Model–view–controller (MVC) Aug 04 2014 [Design] Hadoop Cluster Aug 04 2014 [Google] Find Occurance Greater Than Index Aug 04 2014 [Google] Find Nearest Point in a 2D Space Aug 04 2014 [CC150v4] 17.1 Type a URL in Browser and Hit Enter Aug 03 2014 [Google] Three Keys Data Structure Aug 03 2014 [Design] Multilayered Architecture Aug 03 2014 [Google] Design Solar System (`) Aug 03 2014 [Google] Special Increasing Adjacent Sequence Aug 02 2014 [Google] Print String Comparison Order Aug 02 2014 [Question] Shuffle an Array (Fisher–Yates) Aug 01 2014 [Question] Overriding Private Method Aug 01 2014 [Question] Max Sum in a 2D Array (Sub-matrix) Aug 01 2014 [Question] Arranging Sequence Aug 01 2014 [Question] Run-Length Encoding Jul 31 2014 [Question] Points on Globe Puzzle Jul 31 2014 [Question] Inorder Successor in Binary Search Tree Jul 31 2014 [Question] Peripheral of a Complete Tree Jul 30 2014 [Question] Nth Fibonacci Number in O(LogN) Jul 30 2014 [Question] Which Loop Is Faster Jul 29 2014 [Question] Remove Chars in Pairs Jul 29 2014 [Question] Find Min & Max in an Array Using Minimum Comparisons Jul 29 2014 [Question] Construct a BST From Preorder Traversal Jul 29 2014 [Question] Matching Nuts and Bolts Jul 28 2014 [Question] Check if Number Exists Jul 28 2014 [Question] Breaking Chocolate Bars Jul 28 2014 [LeetCode Plus] Sliding Window Maximum Jul 27 2014 [Question] Reconstruct Tree From Pre-Order Traversal Jul 27 2014 [Question] Fit 1*2 Dominos in 2*N Strip Jul 27 2014 [Question] Elephant and Bananas Jul 27 2014 [LeetCode Plus] Coins in a Line Jul 27 2014 [Question] Truth Tell Brain Teaser Jul 26 2014 [Testing] Test Number Divisibility Jul 26 2014 [Question] Random Number Generate Question Jul 26 2014 [Design] Multithreading Q&A Jul 26 2014 [Design] Big Data - Top K Frequency Jul 25 2014 [Design] Semaphore Mutex Toilet Example Jul 25 2014 [Fundamental] Quickselect Jul 25 2014 [Question] Find 10001st Prime (Sieve of E) Jul 25 2014 [Java OOP] Octal and Hexadecimal Numbers in Java Jul 24 2014 [Design] Multithreading Basics Jul 24 2014 [Question] Find the First Non-repeating Character Jul 24 2014 [LeetCode Plus] Convert BST to Circular DLL Jul 24 2014 [Question] Implement Stack Using Two Queues Jul 23 2014 [Question] Least Number After Deleting Digits Jul 23 2014 [Question] Largest Palindrome Product Jul 23 2014 [Question] Bucket Sort (Bin Sort) Jul 22 2014 [Question] Max Binary Gap Jul 21 2014 [Question] Quick Sort Jul 21 2014 [Java OOP] OOP - 4 Major Principles Jul 21 2014 [Question] Longest Substring With at Most Two Distinct Characters Jul 21 2014 [Octopress] Clone Octopress Blog From a Different Computer Jul 21 2014 [Design] Two's Complement (2's Complement) Jul 13 2014 [NineChap 10] Additional Questions Jul 07 2014 [Question] Subarray With Sum Closest Jul 04 2014 [Question] Subarray With Particular Sum Jul 04 2014 [Question] Subarray With 0 Sum Jul 04 2014 [Question] Check Power of 2 Jul 04 2014 [LintCode] Trailing Zeros of Factorial Jul 02 2014 [Question] the Skyline Problem Jul 01 2014 [Question] Min Stack Jul 01 2014 [Question] Median in a Stream of Integers Jul 01 2014 [Question] Implement Queue Using Stacks Jul 01 2014 [Question] Implement a HashMap Jul 01 2014 [Design] HashMap vs Hashtable vs HashSet Jul 01 2014 [NineChap 9] Big Date, System Design and Resume (`) Jun 30 2014 [Question] 0-1 Knapsack Problem Jun 30 2014 [Question] Make a Fair Coin From a Biased Coin Jun 30 2014 [Question] Coin Change Problem Jun 30 2014 [Question] Single Number IV Jun 28 2014 [Question] Single Number III Jun 28 2014 [LintCode] Partition Array Jun 28 2014 [NineChap 8] High Frequency Questions Jun 28 2014 [NineChap 7] Data Structure Jun 28 2014 [LintCode] Minimum Subarray Jun 28 2014 [LintCode] Maximum Subarray II Jun 28 2014 [LintCode] Majority Number III Jun 28 2014 [LintCode] Majority Number II Jun 28 2014 [LintCode] Majority Number Jun 28 2014 [Question] Topology Sort Jun 27 2014 [LintCode] Previous Permutation Jun 27 2014 [NineChap 6] Graph and Search Jun 26 2014 [Brain Teaser] Khan Academy 8 Brain Teasers Jun 26 2014 [NineChap 5.1] Dynamic Programming Jun 24 2014 [LintCode] Longest Increasing Subsequence Jun 24 2014 [LintCode] Longest Common Subsequence Jun 24 2014 [Design] Cache and Page Replacement Algorithms Jun 23 2014 [Brain Teaser] 2 Eggs 100 Floors Puzzle Jun 18 2014 [Question] Number Sum Sequence Jun 18 2014 [NineChap 4.2] Linked List Additional Jun 18 2014 [Question] Union and Intersection of Two Linked Lists Jun 17 2014 [Design] Time Complexity Calculation (Master Theorem) Jun 17 2014 [LeetCode Plus] Reverse Linked List Iteratively and Recursively Jun 17 2014 [NineChap 4.1] Linked List Jun 16 2014 [LeetCode Plus] Binary Tree Serialize and Deserialize Jun 16 2014 [NineChap 3.4] Binary Tree Additional Jun 15 2014 [Java OOP] Java Global Variable Jun 15 2014 [Question] Binary Search Tree Find Upper/lower Bound Jun 15 2014 [Java OOP] Java Modifier and Access Level Jun 14 2014 [Question] Iterator of Binary Search Tree Jun 14 2014 [Question] Count Negative in a 2D Sorted Matrix Jun 14 2014 [Question] Search Range in BST (Trim a BST) Jun 13 2014 [NineChap 1.2] Permutation Jun 12 2014 [Question] Compare Mergesort and Quicksort Jun 12 2014 [NineChap 1.1] strStr and Coding Style Jun 11 2014 [Design] BST Node Insertion / Deletion Jun 11 2014 [LeetCode Plus] Searching a 2D Sorted Matrix Jun 10 2014 [NineChap 3.1] Binary Tree DFS and Divide Conquer Jun 10 2014 [NineChap 3.2] Binary Tree BFS Jun 10 2014 [NineChap 3.3] Binary Search Tree Jun 10 2014 [LeetCode Plus] Lowest Common Ancestor of Binary Tree (II) Jun 10 2014 [LeetCode Plus] Lowest Common Ancestor of Binary Tree (I) Jun 10 2014 [LeetCode Plus] Lowest Common Ancestor of BST Jun 10 2014 [Question] First Character Appearing Only Once Jun 10 2014 [NineChap 2.2] Sorted Array Jun 09 2014 [LintCode] Recover Rotated Sorted Array Jun 08 2014 [NineChap 2.1] Binary Search Jun 08 2014 [Testing] Software Testing Jun 05 2014 [Question] ASCII, Utf-8, Utf-16 and Unicode Jun 04 2014 [Question] Junit Hand-on Notes Jun 04 2014 [LeetCode 151] Reverse Words in a String Jun 03 2014 [LeetCode 143] Reorder List Jun 03 2014 [LeetCode 149] Max Points on a Line Jun 03 2014 [LeetCode 146] LRU Cache Jun 03 2014 [Design] Implemention of DFS Using a Stack Jun 03 2014 [LeetCode 150] Evaluate Reverse Polish Notation Jun 03 2014 [LeetCode 145] Binary Tree Postorder Traversal Jun 03 2014 [Design] Big Endian and Little Endian Jun 03 2014 [LeetCode 140] Word Break II Jun 02 2014 [LeetCode 139] Word Break Jun 02 2014 [LeetCode 148] Sort List Jun 02 2014 [LeetCode 142] Linked List Cycle II Jun 02 2014 [LeetCode 141] Linked List Cycle Jun 02 2014 [LeetCode 138] Copy List With Random Pointer Jun 02 2014 [LeetCode 144] Binary Tree Preorder Traversal Jun 02 2014 [LeetCode 137] Single Number II Jun 01 2014 [LeetCode 136] Single Number Jun 01 2014 [LeetCode 134] Gas Station May 31 2014 [LeetCode 135] Candy May 31 2014 [LeetCode 126] Word Ladder II (Unsolvable) May 30 2014 [LeetCode 132] Palindrome Partitioning II May 30 2014 [LeetCode 147] Insertion Sort List May 30 2014 [LeetCode 133] Clone Graph May 30 2014 [LeetCode 127] Word Ladder May 29 2014 [LeetCode 130] Surrounded Regions May 29 2014 [LeetCode 129] Sum Root to Leaf Numbers May 29 2014 [LeetCode 131] Palindrome Partitioning May 29 2014 [LeetCode 128] Longest Consecutive Sequence May 29 2014 [Design] DFS, BFS and Space Efficiency May 29 2014 [LeetCode 125] Valid Palindrome May 28 2014 [LeetCode 114] Flatten Binary Tree to Linked List May 28 2014 [LeetCode 124] Binary Tree Maximum Path Sum May 28 2014 [LeetCode 123] Best Time to Buy and Sell Stock III May 28 2014 [LeetCode 122] Best Time to Buy and Sell Stock II May 28 2014 [LeetCode 121] Best Time to Buy and Sell Stock May 28 2014 [LeetCode 120] Triangle May 27 2014 [LeetCode 117] Populating Next Right Pointers in Each Node II May 27 2014 [LeetCode 116] Populating Next Right Pointers in Each Node May 27 2014 [LeetCode 113] Path Sum II May 27 2014 [LeetCode 112] Path Sum May 27 2014 [LeetCode 119] Pascal's Triangle II May 27 2014 [LeetCode 118] Pascal's Triangle May 27 2014 [LeetCode 115] Distinct Subsequences May 27 2014 [LeetCode 105] Construct Binary Tree From Preorder and Inorder May 27 2014 [LeetCode 106] Construct Binary Tree From Inorder and Postorder May 27 2014 [LeetCode 98] Validate Binary Search Tree May 26 2014 [LeetCode 95] Unique Binary Search Trees II May 26 2014 [LeetCode 96] Unique Binary Search Trees May 26 2014 [LeetCode 101] Symmetric Tree May 26 2014 [LeetCode 109] Convert Sorted List to Binary Search Tree May 26 2014 [LeetCode 108] Convert Sorted Array to Binary Search Tree May 26 2014 [LeetCode 110] Balanced Binary Tree May 26 2014 [LeetCode 100] Same Tree May 25 2014 [LeetCode 99] Recover Binary Search Tree May 25 2014 [LeetCode 111] Minimum Depth of Binary Tree May 25 2014 [LeetCode 104] Maximum Depth of Binary Tree May 25 2014 [LeetCode 103] Binary Tree Zigzag Level Order Traversal May 25 2014 [LeetCode 107] Binary Tree Level Order Traversal II May 25 2014 [LeetCode 102] Binary Tree Level Order Traversal May 25 2014 [LeetCode 93] Restore IP Addresses May 24 2014 [LeetCode 85] Maximal Rectangle May 24 2014 [LeetCode 97] Interleaving String May 24 2014 [LeetCode 94] Binary Tree Inorder Traversal May 24 2014 [LeetCode 87] Scramble String May 23 2014 [LeetCode 92] Reverse Linked List II May 23 2014 [LeetCode 86] Partition List May 23 2014 [LeetCode 88] Merge Sorted Array May 23 2014 [LeetCode 84] Largest Rectangle in Histogram May 23 2014 [LeetCode 89] Gray Code May 23 2014 [LeetCode 91] Decode Ways May 23 2014 [LeetCode 90] Subsets II May 22 2014 [LeetCode 78] Subsets May 22 2014 [LeetCode 81] Search in Rotated Sorted Array II May 22 2014 [LeetCode 82] Remove Duplicates From Sorted List II May 22 2014 [LeetCode 83] Remove Duplicates From Sorted List May 22 2014 [LeetCode 80] Remove Duplicates From Sorted Array II May 22 2014 [LeetCode 77] Combinations May 22 2014 [LeetCode 79] Word Search May 21 2014 [LeetCode 69] Sqrt(x) May 21 2014 [LeetCode 75] Sort Colors May 21 2014 [LeetCode 71] Simplify Path May 21 2014 [LeetCode 73] Set Matrix Zeroes May 21 2014 [LeetCode 74] Search a 2D Matrix May 21 2014 [LeetCode 66] Plus One May 21 2014 [LeetCode 76] Minimum Window Substring May 21 2014 [LeetCode 72] Edit Distance May 21 2014 [LeetCode 70] Climbing Stairs May 21 2014 [LeetCode 67] Add Binary May 21 2014 [LeetCode 63] Unique Paths II May 20 2014 [LeetCode 62] Unique Paths May 20 2014 [LeetCode 64] Minimum Path Sum May 20 2014 [LeetCode 53] Maximum Subarray May 20 2014 [LeetCode 61] Rotate List May 19 2014 [LeetCode 60] Permutation Sequence May 19 2014 [LeetCode 65] Valid Number (Unsolvable) May 18 2014 [LeetCode 68] Text Justification (Unsolvable) May 18 2014 [LeetCode 57] Insert Interval May 18 2014 [LeetCode 56] Merge Intervals May 17 2014 [LeetCode 59] Spiral Matrix II May 16 2014 [LeetCode 54] Spiral Matrix May 16 2014 [LeetCode 52] N-Queens II May 16 2014 [LeetCode 51] N-Queens May 16 2014 [LeetCode 58] Length of Last Word May 16 2014 [LeetCode 55] Jump Game May 16 2014 [LeetCode 44] Wildcard Matching May 15 2014 [LeetCode 50] Pow(x, N) May 15 2014 [LeetCode 49] Anagrams May 15 2014 [LeetCode 42] Trapping Rain Water May 14 2014 [LeetCode 37] Sudoku Solver May 14 2014 [LeetCode 48] Rotate Image May 14 2014 [LeetCode 47] Permutations II May 14 2014 [LeetCode 46] Permutations May 14 2014 [LeetCode 43] Multiply Strings May 14 2014 [LeetCode 45] Jump Game II May 14 2014 [LeetCode 41] First Missing Positive May 14 2014 [LeetCode 38] Count and Say May 13 2014 [LeetCode 40] Combination Sum II May 13 2014 [LeetCode 39] Combination Sum May 13 2014 [LeetCode 36] Valid Sudoku May 12 2014 [LeetCode 33] Search in Rotated Sorted Array May 12 2014 [LeetCode 34] Search for a Range May 12 2014 [LeetCode 35] Search Insert Position May 12 2014 [LeetCode 31] Next Permutation May 12 2014 [LeetCode 32] Longest Valid Parentheses May 12 2014 [Fundamental] Heap (Data Structure) May 11 2014 [LeetCode 25] Reverse Nodes in k-Groups May 11 2014 [LeetCode 23] Merge K Sorted Lists May 11 2014 [LeetCode 30] Substring With Concatenation of All Words May 10 2014 [Fundamental] Recap on Java HashMap May 10 2014 [Fundamental] Java Bit Operation May 10 2014 [LeetCode 28] Implement strStr May 10 2014 [LeetCode 29] Divide Two Integers May 10 2014 [LeetCode 20] Valid Parentheses May 09 2014 [LeetCode 24] Swap Nodes in Pairs May 09 2014 [LeetCode 27] Remove Element May 09 2014 [LeetCode 26] Remove Duplicates From Sorted Array May 09 2014 [LeetCode 21] Merge Two Sorted Lists May 09 2014 [LeetCode 22] Generate Parentheses May 09 2014 [LeetCode 18] 4Sum May 03 2014 [LeetCode 19] Remove Nth Node From End of List May 02 2014 [LeetCode 17] Letter Combinations of a Phone Number May 02 2014 [LeetCode 16] 3Sum Closest May 02 2014 [LeetCode 15] 3Sum May 02 2014 [LeetCode 14] Longest Common Prefix May 01 2014 [LeetCode 13] Roman to Integer Apr 30 2014 [LeetCode 12] Integer to Roman Apr 30 2014 [LeetCode 6] ZigZag Conversion Apr 29 2014 [LeetCode 8] String to Integer (Atoi) Apr 29 2014 [LeetCode 10] Regular Expression Matching Apr 29 2014 [LeetCode 9] Palindrome Number Apr 29 2014 [LeetCode 11] Container With Most Water Apr 29 2014 [LeetCode 7] Reverse Integer Apr 28 2014 [LeetCode 5] Longest Palindromic Substring Apr 28 2014 [LeetCode 3] Longest Substring Without Repeating Characters Apr 27 2014 [LeetCode 2] Add Two Numbers Apr 27 2014 [LeetCode 1] Two Sum Apr 26 2014 [LeetCode 4] Median of Two Sorted Arrays Apr 26 2014 LeetCode Statistics Apr 25 2014 2013 [Question] Insert Plus and Minus to Complete Expression Nov 21 2013 [Question] Get Max Number Game (Minmax + Dp) Nov 21 2013 [Amazon] Infix to Postfix Conversion Nov 20 2013 [Question] Shuffle and Get Max Difference Nov 15 2013 [Question] Count Arithmetic Slices Nov 15 2013 [Question] Number of Bus Stations (Meeting Rooms) Nov 05 2013