Problem 18
module Problem_0018
let temp =
@" 75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23"
open System
let getList =
temp.Split('\n')
|> Seq.map(fun s ->
let s = s.Trim()
let len = s.Length - 1
seq { for i in 0..3..len -> int(s.[i..i+1]) }
)
let inline add a b =
match (a,b) with
| (0,_) | (_,0) -> 0
| _ -> a+b;;
/// Toupleで与えられた a と b に c を足し、大きい値を返す。
let inline add2 ((a,b),c) = max (add a c) (add b c)
/// 両端に seq {0} を加える。
let inline getPairSeq s =
let a = seq { yield 0 }
Seq.append (Seq.append a s) a
|> Seq.pairwise
let dp =
getList
|> Seq.fold (fun acm s ->
if Seq.isEmpty acm then s
else
let s2 = getPairSeq acm
Seq.zip (getPairSeq acm) s
|> Seq.map add2
) Seq.empty
|> Seq.max
let run() =
dp