Module day_16

This is my solution for Advent of Code - Day 16: Reindeer Maze

parse_input turns the puzzle input into a Maze

Maze::lowest_scoring_route solves part 1 using A* graph search, with Position tracking the progress through the maze, with Position::next providing next steps from each position, using CoordinateExtensions::manhattan_distance and CoordinateExtensions::turn_cost as the heuristic to estimate remaining distance from a node.

Maze::count_visited_by_best_routes solves part 2, using similar techniques, but running until all possible best routes are found, and analysing Position.visited lists to produce the answer.

Structs

• Maze 🔒
• Position 🔒
  A node in the graph search storing the position and facing, the score and estimated distance to the goal to allow ordering, and a record of the path taken to reach this node.

Enums

• Facing 🔒
  To track the reindeer’s current facing in the maze

Traits

• CoordinateExtensions 🔒
  Helper trait to add methods to the built-in (u8, u8) Coordinate type

Functions

• parse_input 🔒
  Turn the puzzle input into the internal representation.
• run
  The entry point for running the solutions with the ‘real’ puzzle input.

Type Aliases

• Coordinates 🔒