15/one.icl

   1 module one
   2
   3 import Data.Maybe
   4 import StdEnv
   5 from Data.IntMap.Strict import :: IntMap
   6 import qualified Data.IntMap.Strict as DM
   7
   8 input = [6,13,1,15,2,0]
   9 input2 = [0,3,6]
  10
  11 Start = (one, two)
  12
  13 one = speak 2020 input
  14 two = speak 30000000 input
  15
  16 //Old part I version
  17 //speak :: Int [Int] -> Int
  18 //speak num inp = speak` num (reverse inp)
  19 //where
  20 //      speak` 0 spoken = spoken!!length inp
  21 //      speak` idx [ls:spoken] = case [i\\i<-[0..] & s<-spoken | s == ls] of
  22 //              [] = speak` (idx-1) [0,ls:spoken]
  23 //              [i:_] = speak` (idx-1) [i+1,ls:spoken]
  24
  25 speak :: Int [Int] -> Int
  26 speak num inp = speak` (length inp) (last inp)
  27         ('DM'.fromList [(num, idx)\\idx<-[0..] & num <-init inp])
  28 where
  29         speak` :: !Int !Int !(IntMap Int) -> Int
  30         speak` idx last spoken
  31                 | idx == num = last
  32                 = speak` (idx+1) (maybe 0 (\i->idx-i-1) ('DM'.get last spoken)) ('DM'.put last (idx-1) spoken)