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advent-of-code/2020/10/part1.hs
Zach Perrault 2a5b18fb1f
solve: day 10
- solve: day 10, part 1
  - solve: day 10, part 2
2020-12-11 09:55:34 -05:00

15 lines
311 B
Haskell
Executable file

#!/usr/bin/env runghc
import Day10
import Data.List
main = interact (show . solve . parse)
solve xs = ones * threes
where
sorted = 0:(sort xs)
differences = zipWith (flip (-)) sorted (tail sorted)
ones = count 1 differences
threes = count 3 differences + 1
count x = length . filter (==x)