factorization

问题 Thanks for reading. Pretty new to Javascript and programming in general. I'm looking for a way to return the largest prime factor of a given number. My first instinct was to work with a while loop that counts up and finds prime factors of the number, storing the factors in an array and resetting each time it finds one. This way the last item in the array should be the largest prime factor. var primerizer = function(input){ var factors = []; var numStorage = input for (x=2; numStorage != 1; x+

问题 This question already has answers here : Closed 8 years ago . Possible Duplicates: nth ugly number Find the Kth least number for expression (2^x)*(3^y)*(5^z) I'm wondering how to solve this problem in a fast and elegant way: We define "ugly" every number n which can be written in the form: 2^x * 3^y * 5^z;, where x,y and z are natural numbers. Find the 1500th ugly number. E.g. the first "ugly" numbers are: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, ... I've tried to solve this problem using brute

问题 This question already has answers here : Closed 8 years ago . Possible Duplicates: nth ugly number Find the Kth least number for expression (2^x)*(3^y)*(5^z) I'm wondering how to solve this problem in a fast and elegant way: We define "ugly" every number n which can be written in the form: 2^x * 3^y * 5^z;, where x,y and z are natural numbers. Find the 1500th ugly number. E.g. the first "ugly" numbers are: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, ... I've tried to solve this problem using brute

问题 I'm new to Haskell. How to generate a list of lists which contains prime factors of next integers? Currently, I only know how to generate prime numbers: primes = map head $ iterate (\(x:xs) -> [y | y<-xs, y `mod` x /= 0 ]) [2..] 回答1: A simple approach to determine the prime factors of n is to search for the first divisor d in [2..n-1] if D exists: return d : primeFactors(div n d) otherwise return n (since n is prime) Code: prime_factors :: Int -> [Int] prime_factors 1 = [] prime_factors n |

问题 I'm working on a Project Euler problem which requires factorization of an integer. I can come up with a list of all of the primes that are the factor of a given number. The Fundamental Theorem of Arithmetic implies that I can use this list to derive every factor of the number. My current plan is to take each number in the list of base primes and raise its power until it is no longer an integer factor to find the maximum exponents for each prime. Then, I will multiply every possible

问题 While answering another, I stumbled over the question how I actually could find all factors of an integer number without the Symbolic Math Toolbox . For example: factor(60) returns: 2 2 3 5 unique(factor(60)) would therefore return all prime-factors, "1" missing. 2 3 5 And I'm looking for a function which would return all factors ( 1 and the number itself are not important, but they would be nice) Intended output for x = 60 : 1 2 3 4 5 6 10 12 15 20 30 60 I came up with that rather bulky

问题 My normal search foo is failing me. I'm trying to find an R function that returns ALL of the factors of an integer. There are at least 2 packages with factorize() functions: gmp and conf.design, however these functions return only prime factors. I'd like a function that returns all factors. Obviously searching for this is made difficult since R has a construct called factors which puts a lot of noise in the search. 回答1: To follow up on my comment (thanks to @Ramnath for my typo), the brute

问题 I've written a program that attempts to find Amicable Pairs. This requires finding the sums of the proper divisors of numbers. Here is my current sumOfDivisors() method: int sumOfDivisors(int n) { int sum = 1; int bound = (int) sqrt(n); for(int i = 2; i <= 1 + bound; i++) { if (n % i == 0) sum = sum + i + n / i; } return sum; } So I need to do lots of factorization and that is starting to become the real bottleneck in my application. I typed a huge number into MAPLE and it factored it

问题 I'm trying to solve problem 3 from http://projecteuler.net. However, when I run thing program nothing prints out. What am I doing wrong? Problem: What is the largest prime factor of the number 600851475143 ? public class project_3 { public boolean prime(long x) // if x is prime return true { boolean bool = false; for(long count=1L; count<x; count++) { if( x%count==0 ) { bool = false; break; } else { bool = true; } } return bool; } public static void main(String[] args) { long ultprime = 0L; /

问题 I wrote a quick code for factorizing formulas, however the line that takes creates the square root of D doesn’t work. The line is line 10. Any help is appreciated. using System; public class MainClass { //Source Numbers public int A = 1; public int B = 3; public int C = 9; //Calculation Numbers public float Di; public static double Sqrt(double Di); //This is the faulted line. //Answers public float X; public float X1; public float X2; public static void Main() { Console.Writeline("D=", Di); /