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This repository was archived by the owner on Sep 20, 2025. It is now read-only.

Commit 01f79de

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Day 12 Ruby solutions
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‎12-1.rb‎

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#!/usr/bin/env ruby
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require 'numo/narray'
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require 'algorithms'
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class Map
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attr_accessor :start, :end, :map, :lengths
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def initialize(input)
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@height = input.size
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@width = input[0].size
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@map = Numo::UInt8.zeros(@height, @width)
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input.each_index do |row|
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input[row].each_index do |col|
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case input[row][col]
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when 'S'
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@start = [row, col]
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@map[row, col] = 0
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when 'E'
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@end = [row, col]
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@map[row, col] = 'z'.ord - 'a'.ord
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else
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@map[row, col] = input[row][col].ord - 'a'.ord
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end
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end
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end
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@lengths = Numo::UInt32.new(@height, @width).fill Numo::UInt32::MAX
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@lengths[@start[0], @start[1]] = 0
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end
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def solve!
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queue = Containers::MinHeap.new
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queue.push(0, @start)
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until queue.empty?
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length = queue.next_key
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row, col = queue.pop
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next if length > @lengths[row, col]
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neighbours = [
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[row + 1, col],
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[row - 1, col],
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[row, col + 1],
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[row, col - 1]
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]
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neighbours.select! do |coords|
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coords[0] >= 0 and
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coords[0] < @height and
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coords[1] >= 0 and
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coords[1] < @width and
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@map[coords[0], coords[1]] <= @map[row, col] + 1
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end
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neighbours.each do |step|
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new_length = length + 1
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if new_length < @lengths[step[0], step[1]]
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@lengths[step[0], step[1]] = new_length
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queue.push(new_length, [step[0], step[1]])
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end
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end
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end
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@lengths[@end[0], @end[1]]
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end
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def to_s
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s = "<#{self.class}:\n"
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s += "Start: #{@start}, end: #{@end}\n"
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s += "\nMap:\n"
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@height.times do |row|
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@width.times do |col|
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s += @map[row, col].to_s.rjust(2, '0') + ' '
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end
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s += "\n"
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end
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s += "\nLengths:\n"
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@height.times do |row|
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@width.times do |col|
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s += @lengths[row, col].to_s.rjust(Math::log10(@lengths.max).ceil, '0') + ' '
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end
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s += "\n"
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end
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s += '>'
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s
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end
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alias inspect to_s
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end
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input = File.read('12.input').lines.map(&:strip).map(&:chars)
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map = Map.new(input)
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print map.solve!, "\n"

‎12-2.rb‎

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#!/usr/bin/env ruby
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require 'numo/narray'
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require 'algorithms'
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class Map
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attr_accessor :start, :end, :map, :lengths
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def initialize(input)
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@height = input.size
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@width = input[0].size
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@map = Numo::UInt8.zeros(@height, @width)
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input.each_index do |row|
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input[row].each_index do |col|
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case input[row][col]
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when 'S'
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@map[row, col] = 0
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when 'E'
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@start = [row, col]
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@map[row, col] = 'z'.ord - 'a'.ord
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else
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@map[row, col] = input[row][col].ord - 'a'.ord
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end
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end
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end
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@lengths = Numo::UInt32.new(@height, @width).fill Numo::UInt32::MAX
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@lengths[@start[0], @start[1]] = 0
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end
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def solve!
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queue = Containers::MinHeap.new
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queue.push(0, @start)
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until queue.empty?
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length = queue.next_key
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row, col = queue.pop
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next if length > @lengths[row, col]
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neighbours = [
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[row + 1, col],
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[row - 1, col],
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[row, col + 1],
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[row, col - 1]
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]
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neighbours.select! do |coords|
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coords[0] >= 0 and
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coords[0] < @height and
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coords[1] >= 0 and
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coords[1] < @width and
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@map[row, col] <= @map[coords[0], coords[1]] + 1
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end
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neighbours.each do |step|
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new_length = length + 1
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if new_length < @lengths[step[0], step[1]]
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@lengths[step[0], step[1]] = new_length
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queue.push(new_length, [step[0], step[1]])
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end
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end
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end
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end
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def solution
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closest = Numo::UInt32::MAX
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@map.each_with_index do |height, row, col|
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next if height.positive?
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if @lengths[row, col] < closest
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closest = @lengths[row, col]
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end
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end
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closest
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end
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def to_s
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s = "<#{self.class}:\n"
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s += "Start: #{@start}, end: #{@end}\n"
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s += "\nMap:\n"
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@height.times do |row|
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@width.times do |col|
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s += @map[row, col].to_s.rjust(2, '0') + ' '
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end
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s += "\n"
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end
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s += "\nLengths:\n"
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@height.times do |row|
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@width.times do |col|
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s += @lengths[row, col].to_s.rjust(Math::log10(@lengths.max).ceil, '0') + ' '
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end
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s += "\n"
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end
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s += '>'
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s
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end
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alias inspect to_s
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end
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input = File.read('12.input').lines.map(&:strip).map(&:chars)
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map = Map.new(input)
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map.solve!
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print map.solution, "\n"

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