Comments on: Project Euler Problem 3 in F#

By: Dilip

Dilip — Wed, 21 Sep 2011 22:47:00 +0000

Same problem solved in C#

https://sites.google.com/site/eulerproblemsincsharp/home/problem-3

By: Stephen, of Adelaide

Stephen, of Adelaide — Fri, 01 Oct 2010 09:22:00 +0000

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Stephen, of Adelaide

Stephen, of Adelaide — Fri, 01 Oct 2010 09:21:00 +0000

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:10:24 +0000

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:10:00 +0000

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:07:19 +0000

Well, that didn’t work very well! Try again without the pre tag. I’m afraid that was my best shot at formatting it.

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:07:00 +0000

Well, that didn’t work very well! Try again without the pre tag. I’m afraid that was my best shot at formatting it.

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:05:16 +0000

Thanks Stefan for your replies to my comments on problems 4 and 5!

I’m thinking that this code is probably just too difficult to read. It was certainly difficult to write. I’ll re-post it, with a few changes:

- Build a list of prime factors, instead of just finding the largest. Then one can see it working
a bit more clearly. After the list is built, use Seq.max to get the largest. (I built this version first, before the final version which extracts the largest during the intermediate work).
- Use more standard naming conventions (“i” instead of “fromN”, “acc” for the accumulator). I like the wordier versions to keep track of what I’m doing when developing.
- Add some comments
- Try to format the code.

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Thu, 30 Sep 2010 02:05:00 +0000

Thanks Stefan for your replies to my comments on problems 4 and 5!

I’m thinking that this code is probably just too difficult to read. It was certainly difficult to write. I’ll re-post it, with a few changes:

let Problem3 n =
let rec PrimeFactors n i acc =
// Read as: Add the prime factors of n to the accumulator, given that
// 0..i – 1 are not factors.
if n Seq.max

By: Javaman59

Javaman59 — Wed, 29 Sep 2010 11:23:35 +0000

I skipped that last line of my solution…

Aux n 1L 2L