factorial

the number of trailing zeros in a factorial of a given number - Ruby

由 不羁岁月 提交于 2019-11-27 06:47:57
问题 Having a little trouble trying calculate the number of trailing zeros in a factorial of a given number. This is one of the challenges from Codewars- can't get mine to pass. zeros(12) = 2 #=> 1 * 2 * 3 .. 12 = 479001600 I think I'm on the wrong path here and there is probably a more elegant ruby way. This is what I have down so far. def zeros(n) x = (1..n).reduce(:*).to_s.scan(/[^0]/) return 0 if x == [] return x[-1].length if x != [] end 回答1: This is more of a math question. And you're right,

Factorial Memoization in R

由 醉酒当歌 提交于 2019-11-27 06:27:50
问题 I wrote this function to find a factorial of number fact <- function(n) { if (n < 0){ cat ("Sorry, factorial does not exist for negative numbers", "\n") } else if (n == 0){ cat ("The factorial of 0 is 1", "\n") } else { results = 1 for (i in 1:n){ results = results * i } cat(paste("The factorial of", n ,"is", results, "\n")) } } Now I want to implement Memoization in R. I have Basic idea on R and trying to implement using them. But I am not sure is this way forward. Could you please also

Understanding factorial recursion [duplicate]

由 孤街浪徒 提交于 2019-11-27 06:18:33
问题 This question already has an answer here: Understanding recursion in Python 4 answers I'm looking over the factorial example of recursion and would just like to make sure that I'm understanding it correctly! def factorial(n): if n == 0: return 1 else: return n * factorial(n - 1) Would I be right in saying: factorial(4) = factorial(4-1) * 4 = factorial(3-1) *3 *4 = factorial(2-1) *2 *3 *4 = factorial(1-1) *1 *2 *3 *4 = 24 because factorial(1-1) = factorial(0) which as the base case shows = 1

Ruby factorial function

由 旧巷老猫 提交于 2019-11-27 04:13:09
问题 I'm going crazy: Where is the Ruby function for factorial? No, I don't need tutorial implementations, I just want the function from the library. It's not in Math! I'm starting to doubt, is it a standard library function? 回答1: There is no factorial function in the standard library. 回答2: Like this is better (1..n).inject(:*) || 1 回答3: It's not in the standard library but you can extend the Integer class. class Integer def factorial_recursive self <= 1 ? 1 : self * (self - 1).factorial end def

How do I find a factorial? [closed]

由 旧城冷巷雨未停 提交于 2019-11-27 04:12:38
How can I write a program to find the factorial of any natural number? This will work for the factorial (although a very small subset) of positive integers: unsigned long factorial(unsigned long f) { if ( f == 0 ) return 1; return(f * factorial(f - 1)); } printf("%i", factorial(5)); Due to the nature of your problem (and level that you have admitted), this solution is based more in the concept of solving this rather than a function that will be used in the next "Permutation Engine". This calculates factorials of non-negative integers[*] up to ULONG_MAX, which will have so many digits that it's

For loop to calculate factorials

由 孤者浪人 提交于 2019-11-27 01:23:21
问题 Currently I have this set of code and its meant to calculate factorials. int numberInt = int.Parse(factorialNumberTextBox.Text); for (int i = 1; i < numberInt; i++) { numberInt = numberInt * i; } factorialAnswerTextBox.Text = numberInt.ToString(); For some reason it doesn't work and i have no clue why. For example i will input 3 and get the answer as -458131456 which seems really strange. Any help appreciated. Thanks 回答1: int numberInt = int.Parse(factorialNumberTextBox.Text); int result =

Find factorial of large numbers in Java

由 久未见 提交于 2019-11-26 23:05:24
问题 I tried to find the factorial of a large number e.g. 8785856 in a typical way using for-loop and double data type. But it is displaying infinity as the result, may be because it is exceeding its limit. So please guide me the way to find the factorial of a very large number. My code: class abc { public static void main (String[]args) { double fact=1; for(int i=1;i<=8785856;i++) { fact=fact*i; } System.out.println(fact); } } Output:- Infinity I am new to Java but have learned some concepts of

Calculating large factorials in C++

由 流过昼夜 提交于 2019-11-26 22:54:19
问题 I understand this is a classic programming problem and therefore I want to be clear I'm not looking for code as a solution, but would appreciate a push in the right direction. I'm learning C++ and as part of the learning process I'm attempting some programming problems. I'm attempting to write a program which deals with numbers up to factorial of 1billion. Obviously these are going to be enormous numbers and way too big to be dealing with using normal arithmetic operations. Any indication as

Why is math.factorial much slower in Python 2.x than 3.x?

由 拈花ヽ惹草 提交于 2019-11-26 22:47:42
问题 I get the following results on my machine: Python 3.2.2 (default, Sep 4 2011, 09:51:08) [MSC v.1500 32 bit (Intel)] on win 32 Type "help", "copyright", "credits" or "license" for more information. >>> import timeit >>> timeit.timeit('factorial(10000)', 'from math import factorial', number=100) 1.9785256226699202 >>> Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)] on win 32 Type "help", "copyright", "credits" or "license" for more information. >>> import timeit >>>

Reversible numerical calculations in Prolog

由 白昼怎懂夜的黑 提交于 2019-11-26 20:17:57
问题 While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables ( C and D ), a new syntax ( is ) and that the problem is
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