R/day23.R
In tjmahr/adventofcode21:
#' Day 23: Amphipod
#'
#' [Amphipod](https://adventofcode.com/2021/day/23)
#'
#' @name day23
#' @rdname day23
#' @details
#'
#' **Part One**
#'
#' A group of [amphipods](https://en.wikipedia.org/wiki/Amphipoda) notice
#' your fancy submarine and flag you down. \"With such an impressive
#' shell,\" one amphipod
#' [says]{title="What? You didn't know amphipods can talk?"}, \"surely you
#' can help us with a question that has stumped our best scientists.\"
#'
#' They go on to explain that a group of timid, stubborn amphipods live in
#' a nearby burrow. Four types of amphipods live there: *Amber* (`A`),
#' *Bronze* (`B`), *Copper* (`C`), and *Desert* (`D`). They live in a
#' burrow that consists of a *hallway* and four *side rooms*. The side
#' rooms are initially full of amphipods, and the hallway is initially
#' empty.
#'
#' They give you a *diagram of the situation* (your puzzle input),
#' including locations of each amphipod (`A`, `B`, `C`, or `D`, each of
#' which is occupying an otherwise open space), walls (`#`), and open space
#' (`.`).
#'
#' For example:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #A#D#C#A#
#' #########
#'
#' The amphipods would like a method to organize every amphipod into side
#' rooms so that each side room contains one type of amphipod and the types
#' are sorted `A`-`D` going left to right, like this:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' Amphipods can move up, down, left, or right so long as they are moving
#' into an unoccupied open space. Each type of amphipod requires a
#' different amount of *energy* to move one step: Amber amphipods require
#' `1` energy per step, Bronze amphipods require `10` energy, Copper
#' amphipods require `100`, and Desert ones require `1000`. The amphipods
#' would like you to find a way to organize the amphipods that requires the
#' *least total energy*.
#'
#' However, because they are timid and stubborn, the amphipods have some
#' extra rules:
#'
#' - Amphipods will never *stop on the space immediately outside any
#' room*. They can move into that space so long as they immediately
#' continue moving. (Specifically, this refers to the four open spaces
#' in the hallway that are directly above an amphipod starting
#' position.)
#' - Amphipods will never *move from the hallway into a room* unless that
#' room is their destination room *and* that room contains no amphipods
#' which do not also have that room as their own destination. If an
#' amphipod\'s starting room is not its destination room, it can stay
#' in that room until it leaves the room. (For example, an Amber
#' amphipod will not move from the hallway into the right three rooms,
#' and will only move into the leftmost room if that room is empty or
#' if it only contains other Amber amphipods.)
#' - Once an amphipod stops moving in the hallway, *it will stay in that
#' spot until it can move into a room*. (That is, once any amphipod
#' starts moving, any other amphipods currently in the hallway are
#' locked in place and will not move again until they can move fully
#' into a room.)
#'
#' In the above example, the amphipods can be organized using a minimum of
#' `12521` energy. One way to do this is shown below.
#'
#' Starting configuration:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #A#D#C#A#
#' #########
#'
#' One Bronze amphipod moves into the hallway, taking 4 steps and using
#' `40` energy:
#'
#' #############
#' #...B.......#
#' ###B#C#.#D###
#' #A#D#C#A#
#' #########
#'
#' The only Copper amphipod not in its side room moves there, taking 4
#' steps and using `400` energy:
#'
#' #############
#' #...B.......#
#' ###B#.#C#D###
#' #A#D#C#A#
#' #########
#'
#' A Desert amphipod moves out of the way, taking 3 steps and using `3000`
#' energy, and then the Bronze amphipod takes its place, taking 3 steps and
#' using `30` energy:
#'
#' #############
#' #.....D.....#
#' ###B#.#C#D###
#' #A#B#C#A#
#' #########
#'
#' The leftmost Bronze amphipod moves to its room using `40` energy:
#'
#' #############
#' #.....D.....#
#' ###.#B#C#D###
#' #A#B#C#A#
#' #########
#'
#' Both amphipods in the rightmost room move into the hallway, using `2003`
#' energy in total:
#'
#' #############
#' #.....D.D.A.#
#' ###.#B#C#.###
#' #A#B#C#.#
#' #########
#'
#' Both Desert amphipods move into the rightmost room using `7000` energy:
#'
#' #############
#' #.........A.#
#' ###.#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' Finally, the last Amber amphipod moves into its room, using `8` energy:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' *What is the least energy required to organize the amphipods?*
#'
#' **Part Two**
#'
#' As you prepare to give the amphipods your solution, you notice that the
#' diagram they handed you was actually folded up. As you unfold it, you
#' discover an extra part of the diagram.
#'
#' Between the first and second lines of text that contain amphipod
#' starting positions, insert the following lines:
#'
#' #D#C#B#A#
#' #D#B#A#C#
#'
#' So, the above example now becomes:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' The amphipods still want to be organized into rooms similar to before:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' In this updated example, the least energy required to organize these
#' amphipods is `44169`:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #..........D#
#' ###B#C#B#.###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A.........D#
#' ###B#C#B#.###
#' #D#C#B#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A........BD#
#' ###B#C#.#.###
#' #D#C#B#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A......B.BD#
#' ###B#C#.#.###
#' #D#C#.#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#C#.#.###
#' #D#C#.#.#
#' #D#B#.#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#.#.#.###
#' #D#C#.#.#
#' #D#B#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#B#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA...B.B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.D.B.B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#.#C#A#
#' #########
#'
#' #############
#' #AA.D...B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D.....BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#B#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D......D#
#' ###B#.#.#.###
#' #D#B#C#.#
#' #D#B#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D......D#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D.....AD#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#.#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###.#B#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #D#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.D.....AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #.#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #A..D.....AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #...D.....AD#
#' ###.#B#C#.###
#' #A#B#C#.#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #.........AD#
#' ###.#B#C#.###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #..........D#
#' ###A#B#C#.###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' Using the initial configuration from the full diagram, *what is the
#' least energy required to organize the amphipods?*
#'
#' **Note: solved by hand**
NULL
tjmahr/adventofcode21 documentation built on Jan. 8, 2022, 10:41 a.m.
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#' Day 23: Amphipod
#'
#' [Amphipod](https://adventofcode.com/2021/day/23)
#'
#' @name day23
#' @rdname day23
#' @details
#'
#' **Part One**
#'
#' A group of [amphipods](https://en.wikipedia.org/wiki/Amphipoda) notice
#' your fancy submarine and flag you down. \"With such an impressive
#' shell,\" one amphipod
#' [says]{title="What? You didn't know amphipods can talk?"}, \"surely you
#' can help us with a question that has stumped our best scientists.\"
#'
#' They go on to explain that a group of timid, stubborn amphipods live in
#' a nearby burrow. Four types of amphipods live there: *Amber* (`A`),
#' *Bronze* (`B`), *Copper* (`C`), and *Desert* (`D`). They live in a
#' burrow that consists of a *hallway* and four *side rooms*. The side
#' rooms are initially full of amphipods, and the hallway is initially
#' empty.
#'
#' They give you a *diagram of the situation* (your puzzle input),
#' including locations of each amphipod (`A`, `B`, `C`, or `D`, each of
#' which is occupying an otherwise open space), walls (`#`), and open space
#' (`.`).
#'
#' For example:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #A#D#C#A#
#' #########
#'
#' The amphipods would like a method to organize every amphipod into side
#' rooms so that each side room contains one type of amphipod and the types
#' are sorted `A`-`D` going left to right, like this:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' Amphipods can move up, down, left, or right so long as they are moving
#' into an unoccupied open space. Each type of amphipod requires a
#' different amount of *energy* to move one step: Amber amphipods require
#' `1` energy per step, Bronze amphipods require `10` energy, Copper
#' amphipods require `100`, and Desert ones require `1000`. The amphipods
#' would like you to find a way to organize the amphipods that requires the
#' *least total energy*.
#'
#' However, because they are timid and stubborn, the amphipods have some
#' extra rules:
#'
#' - Amphipods will never *stop on the space immediately outside any
#' room*. They can move into that space so long as they immediately
#' continue moving. (Specifically, this refers to the four open spaces
#' in the hallway that are directly above an amphipod starting
#' position.)
#' - Amphipods will never *move from the hallway into a room* unless that
#' room is their destination room *and* that room contains no amphipods
#' which do not also have that room as their own destination. If an
#' amphipod\'s starting room is not its destination room, it can stay
#' in that room until it leaves the room. (For example, an Amber
#' amphipod will not move from the hallway into the right three rooms,
#' and will only move into the leftmost room if that room is empty or
#' if it only contains other Amber amphipods.)
#' - Once an amphipod stops moving in the hallway, *it will stay in that
#' spot until it can move into a room*. (That is, once any amphipod
#' starts moving, any other amphipods currently in the hallway are
#' locked in place and will not move again until they can move fully
#' into a room.)
#'
#' In the above example, the amphipods can be organized using a minimum of
#' `12521` energy. One way to do this is shown below.
#'
#' Starting configuration:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #A#D#C#A#
#' #########
#'
#' One Bronze amphipod moves into the hallway, taking 4 steps and using
#' `40` energy:
#'
#' #############
#' #...B.......#
#' ###B#C#.#D###
#' #A#D#C#A#
#' #########
#'
#' The only Copper amphipod not in its side room moves there, taking 4
#' steps and using `400` energy:
#'
#' #############
#' #...B.......#
#' ###B#.#C#D###
#' #A#D#C#A#
#' #########
#'
#' A Desert amphipod moves out of the way, taking 3 steps and using `3000`
#' energy, and then the Bronze amphipod takes its place, taking 3 steps and
#' using `30` energy:
#'
#' #############
#' #.....D.....#
#' ###B#.#C#D###
#' #A#B#C#A#
#' #########
#'
#' The leftmost Bronze amphipod moves to its room using `40` energy:
#'
#' #############
#' #.....D.....#
#' ###.#B#C#D###
#' #A#B#C#A#
#' #########
#'
#' Both amphipods in the rightmost room move into the hallway, using `2003`
#' energy in total:
#'
#' #############
#' #.....D.D.A.#
#' ###.#B#C#.###
#' #A#B#C#.#
#' #########
#'
#' Both Desert amphipods move into the rightmost room using `7000` energy:
#'
#' #############
#' #.........A.#
#' ###.#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' Finally, the last Amber amphipod moves into its room, using `8` energy:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #########
#'
#' *What is the least energy required to organize the amphipods?*
#'
#' **Part Two**
#'
#' As you prepare to give the amphipods your solution, you notice that the
#' diagram they handed you was actually folded up. As you unfold it, you
#' discover an extra part of the diagram.
#'
#' Between the first and second lines of text that contain amphipod
#' starting positions, insert the following lines:
#'
#' #D#C#B#A#
#' #D#B#A#C#
#'
#' So, the above example now becomes:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' The amphipods still want to be organized into rooms similar to before:
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' In this updated example, the least energy required to organize these
#' amphipods is `44169`:
#'
#' #############
#' #...........#
#' ###B#C#B#D###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #..........D#
#' ###B#C#B#.###
#' #D#C#B#A#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A.........D#
#' ###B#C#B#.###
#' #D#C#B#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A........BD#
#' ###B#C#.#.###
#' #D#C#B#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #A......B.BD#
#' ###B#C#.#.###
#' #D#C#.#.#
#' #D#B#A#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#C#.#.###
#' #D#C#.#.#
#' #D#B#.#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#.#.#.###
#' #D#C#.#.#
#' #D#B#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.....B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#B#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA...B.B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#D#C#A#
#' #########
#'
#' #############
#' #AA.D.B.B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#.#C#A#
#' #########
#'
#' #############
#' #AA.D...B.BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#.#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D.....BD#
#' ###B#.#.#.###
#' #D#.#C#.#
#' #D#B#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D......D#
#' ###B#.#.#.###
#' #D#B#C#.#
#' #D#B#C#C#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D......D#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#A#
#' #########
#'
#' #############
#' #AA.D.....AD#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#.#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###B#.#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###.#B#C#.###
#' #D#B#C#.#
#' #D#B#C#.#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.......AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #D#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #AA.D.....AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #.#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #A..D.....AD#
#' ###.#B#C#.###
#' #.#B#C#.#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #...D.....AD#
#' ###.#B#C#.###
#' #A#B#C#.#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #.........AD#
#' ###.#B#C#.###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #..........D#
#' ###A#B#C#.###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' #############
#' #...........#
#' ###A#B#C#D###
#' #A#B#C#D#
#' #A#B#C#D#
#' #A#B#C#D#
#' #########
#'
#' Using the initial configuration from the full diagram, *what is the
#' least energy required to organize the amphipods?*
#'
#' **Note: solved by hand**
NULL
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