The least common multiple (lcm) of a and b is their product divided by their greatest common divisor (gcd) ( i.e. lcm(a, b) = ab/gcd(a,b)). So, the question becomes, how to find the gcd? The Euclidean algorithm is generally how the gcd is computed. The direct implementation of the classic algorithm is efficient, but there are variations that take advantage of binary … Read more
Here’s a reusable function you can use. It includes doctests and data validation: You can run test code by adding: Running the interpolation on your dataset produces:
You can search for (1…100)! on Wolfram|Alpha to pre-calculate the factorial sequence. The first 100 numbers are: If you still want to calculate the values yourself, you can use memoization: Edit: 21.08.2014 Solution 2 I thought it would be useful to add a working example of lazy iterative factorial function that uses big numbers to get exact result with memoization and cache as comparison I assume you would use some kind … Read more
x % 10 looks like the correct answer. But is not. -2 % 10 is either -2 or 8 depending on language/implementation/whatever. And neither is actually “last digit”. So the correct answer is abs(x) % 10.
It’s not ideal, but according to the Lua 5.2 Reference Manual: a % b == a – math.floor(a/b)*b
You can use negative numbers to round integers: Thus if you need only most significant digit: You’ll probably have to take care of turning float to integer if it’s bigger than 1.
There’s no such function, but will do the trick.
For some number y and some divisor x compute the quotient (quotient) and remainder (remainder) as:
For some number y and some divisor x compute the quotient (quotient) and remainder (remainder) as:
!= means “not equal to” and is a logical comparison. Break down the logical expression here: