computer-science

问题 I have tried to find examples of tail recursion and I really don't see the difference between regular and tail. If this isn't tail recursion, can someone tell me why its not? public static long fib(long index) { // assume index >= 0 if (index == 0) // Base case return 0; else if (index == 1) // Base case return 1; else // Reduction and recursive calls return fib(index - 1) + fib(index - 2); } // end of method fib(long index) 回答1: No, the method in the question does not use a tail recursion. A

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 6 years ago . According to this article on denotational semantics in haskell All types have bottom, and a function f:A->B is strict if it maps the

问题 I've read descriptions online describing big and little endian. However, they all seem to basically read the same way and I am still confused on the the actual implementation regarding "most" and "least" significant bytes. I understand that little endian values evaluate the "least significant" values first and under big endian the "most significant" bytes are evaluated first. However, I'm unclear as to the meaning of "most" and "least" significant. I think it would help me to understand if I

问题 Every time I program I recognize this relationship between classes and tables, or am I imagining it. You can have a class per database table or a table per class i.e. : tables: customer, products, order. classes: customer, products, order, may have methods such as addRecord, deleteRecord, updateRecord. what is this called? Object-Relational? I am not a DBA. 回答1: It all depends on the type of database you're using. If you're using an object oriented database (OODB), then there is no

问题 Consider this simulation in the official raft webpage Why is term 2 index 1 not committed despite S2 (leader) , S3 and S4 agreeing on the log? I run this multiple minutes to make sure all communication has taken place. Weirdly enough, if I add one more log entry term 6 index 2 then term 2 index 1 will be committed. Does anyone know what is the rule that is preventing term 2 index 1 to be committed? 回答1: Your leader is in term 6, but none of the log entries are from term 6; this invokes a

问题 For those who used apt-get, you know that everytime you install / uninstall something, you get the notificatons saying you need / no longer need certain dependencies. I'm trying to understand the theory behinds this and potentially implement my own version of this. I've done some googling, came up with mostly coupling stuff. From what I understand, coupling is 2 classes/modules that depends on each other. This is not exactly what I'm looking for. What I'm looking for is more like a

问题 I am a beginner in opencv. I am using opencv v2.1. I have converted an RGB image to HSV image. Now I want to obtain single channels Hue, Value and Saturation separately. What should I do? I have seen similar questions here but No-one answered that. Kindly help. 回答1: You can access the same way you were accessing for RGB image where 1st channel will be for H, 2nd channel for S and 3rd channel for V. If you are using OpenCV 2.1, you must be using IplImage then, right? like if your HSV image is

问题 Not a 'pure' programming question, but since it is deeply involved in programming theory, I thought it best to ask here. Regarding the P NP problem, this excerpt from http://en.wikipedia.org/wiki/P_versus_NP_problem : "In essence, the question P = NP? asks: Suppose that yes answers to a yes or no question can be verified quickly. Then, can the answers themselves also be computed quickly?" I am left wondering, how is the speed of verifying an answer related to the speed of generating a

问题 When I try to write some css through Vnext or Webmatrix v2 beta I got error that unxpected token : sometime I change something and got error that unexpected error ; When I try this body { background-color :Aqua; } I wonder all browser (moz,chrome) give me error that "Uncaught SyntaxError: Unexpected token :" Later I save it from vs2010 but i still have error. Can someone tell me where I am doing wrong. 回答1: The error suggests that you're trying to load your CSS as if it were Javascript. 回答2:

问题 I'm having a hard time conceptualizing c++ sets, actually sets in general. What are they? How are they useful? 回答1: Don't feel bad if you have trouble understanding sets in general. Most of a degree in mathematics is spent coming to terms with set theory: http://en.wikipedia.org/wiki/Set_theory Think of a set as a collection of unique, unordered objects. In many ways it looks like a list: { 1, 2, 3, 4 } but order is unimportant: { 4, 3, 2, 1} = { 1, 2, 3, 4} and repetitions are ignored: { 1,