Project Euler – Problem 39 Solution


If p is the perimeter of a right angle triangle with integral length sides, {a,b,c}, there are exactly three solutions for p = 120.

{20,48,52}, {24,45,51}, {30,40,50}

For which value of p <= 1000, is the number of solutions maximised?


// define function to find the number of solutions for p
let countSolutions p =
    |> List.filter (fun c ->
        |> Seq.takeWhile (fun b -> b + c < p)
        |> Seq.exists (fun b -> (pown (p-b-c) 2 + pown b 2) = pown c 2))
    |> List.length

let answer = [1..1000] |> List.maxBy countSolutions
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