Integer to English Words Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 – 1. For example, 123 -> “One Hundred Twenty Three” 12345 -> “Twelve Thousand Three Hundred Forty Five” 1234567 -> “One Million Two Hundred Thirty Four Thousand Five […]
Bulls and Cows You are playing the following Bulls and Cows game with your friend: You write a 4-digit secret number and ask your friend to guess it, each time your friend guesses a number, you give a hint, the hint tells your friend how many digits are in the […]
Binary Tree Longest Consecutive Sequence Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from parent to […]
Serialize and Deserialize Binary Tree 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 connection link to be reconstructed later in the same or another computer […]
Coursera Note Sentence in red is my own perspective, inspired by the instructor. 1.1 Programming Paradigms Imperative Programs and Computers There is strong correspondence between Mutable variables ~ Memory cells Variable dereference ~ load instructions Variable assignments ~ store instructions Control structures ~ jumps Problem: how can we avoid conceptualizing […]
Best Meeting Point A group of people wants to meet and minimize the total travel distance. You are given a 2D grid of values 0 or 1, where each 1 marks the home of someone in the group. The distance is calculated using Manhattan Distance, where distance(p1, p2) = |p2.x […]
Find Median from Data Stream Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value. Examples: [2,3,4] , the median is 3 [2,3], the median is […]
关于如何在命令行下run一个Hello world的jetty程序。 首先下载两个依赖包 http://mvnrepository.com/artifact/javax.servlet/servlet-api/2.5 http://mvnrepository.com/artifact/org.eclipse.jetty.aggregate/jetty-all/7.0.2.v20100331 将它们放在一个文件夹下，然后新建一个HelloWorld.java的文件，填入如下代码： import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.ServletException; import java.io.IOException; import org.eclipse.jetty.server.Server; import org.eclipse.jetty.server.Request; import org.eclipse.jetty.server.handler.AbstractHandler; public class HelloWorld extends AbstractHandler { public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType(“text/html;charset=utf-8”); response.setStatus(HttpServletResponse.SC_OK); baseRequest.setHandled(true); response.getWriter().println(“<h1>Hello World</h1>”); } public static void main(String[] args) […]
Count Complete Tree Nodes Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia: In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. It […]
Flip Game You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take turns to flip two consecutive”++” into “–“. The game ends when a person can no longer make a move and therefore […]
