Day21

Copyright	(c) Eric Mertens 2021
License	ISC
Maintainer	emertens@gmail.com
Safe Haskell	None
Language	Haskell2010

Main

Contents

Counting Nondeterminism Computations
Modular arithmetic

Description

https://adventofcode.com/2021/day/21

Synopsis

main :: IO ()
part1 :: Int -> Int -> Int -> Int -> Int -> Int
part2 :: Int -> Int -> Int -> Int -> Paths Bool
threeRolls :: Paths Int
newtype Paths a = Paths (WriterT (Product Int) [] a)
runPaths :: Paths a -> [(a, Int)]
gather :: Ord a => Paths a -> Paths a
wrap :: Int -> Int -> Int

Documentation

main :: IO () Source #

>>> :main
428736
57328067654557

Arguments

:: Int	turn counter
-> Int	player 1 location
-> Int	player 2 location
-> Int	player 1 score
-> Int	player 2 score
-> Int	player 2 score * 3 * turns

Compute the die rolls * losing score once one player wins with 1000 points.

Arguments

:: Int	player 1 location
-> Int	player 2 location
-> Int	player 1 score
-> Int	player 2 score
-> Paths Bool	player 1 won

Compute the possible ways a the players can win while playing with a 3-sided dice given some starting conditions.

threeRolls :: Paths Int Source #

Sum of 3d3.

Counting Nondeterminism Computations

newtype Paths a Source #

Nondeterministic computation that can consolidate paths returning the same value.

Constructors

Paths (WriterT (Product Int) [] a)

runPaths :: Paths a -> [(a, Int)] Source #

Return all values and counts from all the paths.

gather :: Ord a => Paths a -> Paths a Source #

Combine the counts of equal outputs to reduce braching factor.

Modular arithmetic

Arguments

:: Int	value
-> Int	bound
-> Int

Wrap number between 1 and an inclusive upper bound