biginteger

问题 I'm trying to solve Fibonacci using java, but my code takes so long with big numbers. Problem Description Task. Given an integer 𝑛, find the last digit of the 𝑛th Fibonacci number 𝐹𝑛 (that is, 𝐹𝑛 mod 10). Input Format. The input consists of a single integer 𝑛. Constraints. 0 ≤ 𝑛 ≤ 10⁷. Output Format. Output the last digit of 𝐹𝑛 . My code: public class FibonacciLastDigit { private static int getFibonacciLastDigitNaive(int n) { if (n <= 1) { return n; } BigInteger first = BigInteger.ZERO;

问题 how to handle integers like 10^200 or larger than that in C language? it won't work even I use long long. then what should I do? I heard about big integer. but don't know how to work with it. as far i know it is a library function for C#. but I am working with C. is there any other way except big integer to work with such large integers? and can someone also explain me how to use big integer? To clarify, I'm only looking for a solution that will work in C. 回答1: See similair question. In short

问题 Can you use BigInteger.isProbablePrime() to generate cryptographically secure primes? What certainty is necessary for them to be "secure"? 回答1: I do not hold a degree in crypto, so take this with a grain of salt. You have two major areas of concern here: Your primes need to be unpredictably random. This means that you need to use a source such as SecureRandom to generate your primes. No matter how sure of your primality, if they are predictable, the entire cryptosystem fails to meet its goal.

问题 Well I can find many big integer libraries but they are for all programming languages except VB.NET. Does anyone know a class/library for Visual Basic .NET which can handle very big numbers? (I'd like to handle 1024 or even more bits). The only calculation support I need it addition, substitution, multiplication, division and rounding. It's ment to be used with this code: Dim Letterz() As Integer = {33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

问题 Well I can find many big integer libraries but they are for all programming languages except VB.NET. Does anyone know a class/library for Visual Basic .NET which can handle very big numbers? (I'd like to handle 1024 or even more bits). The only calculation support I need it addition, substitution, multiplication, division and rounding. It's ment to be used with this code: Dim Letterz() As Integer = {33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

问题 Well I can find many big integer libraries but they are for all programming languages except VB.NET. Does anyone know a class/library for Visual Basic .NET which can handle very big numbers? (I'd like to handle 1024 or even more bits). The only calculation support I need it addition, substitution, multiplication, division and rounding. It's ment to be used with this code: Dim Letterz() As Integer = {33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

问题 I need some division algorithm which can handle big integers (128-bit). I've already asked how to do it via bit shifting operators. However, my current implementation seems to ask for a better approach Basically, I store numbers as two long long unsigned int 's in the format A * 2 ^ 64 + B with B < 2 ^ 64 . This number is divisible by 24 and I want to divide it by 24 . My current approach is to transform it like A * 2 ^ 64 + B A B -------------- = ---- * 2^64 + ---- 24 24 24 A A mod 24 B B

问题 In java , BigInteger is immutable but I want to understand why because a lot of times it is used to do a lot of calculations which can produce a lot of objects. So , it feels kind of intuitive to not make it immutable. The situation which comes to my mind is something like of string operations and then the option of StringBuilder. Should there be non-immutable counterpart of BigInteger ? I think it might be beneficial in a lot of situations. Edit: I know the benefits of immutability and how

问题 I was debating whether to use BigDecimal and BigInteger or only BigDecimal to make my life easier and less converting back and forth. Is there a downside to only using BigDecimal in regards to resources? How about using only primitive data types and BigInteger or only BigInteger to make my life easier and less converting back and forth? 回答1: From: http://www.javamex.com/tutorials/math/BigDecimal_BigInteger_performance.shtml Note that a BigDecimal is essentially a wrapper around a BigInteger

问题 using Org.BouncyCastle.Math; string p = "E7A69EBDF105F2A6BBDEAD7E798F76A209AD73FB466431E2E7352ED262F8C558F10BEFEA977DE9E21DCEE9B04D245F300ECCBBA03E72630556D011023F9E857F"; BigInteger P= new BigInteger(p); throwing Exception System.FormatException: Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffe r& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style,