70 lines
1.5 KiB
Ruby
70 lines
1.5 KiB
Ruby
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#!/bin/env ruby
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require 'pry'
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def turn_ship (direction, degree, facing)
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dirs = [:north, :east, :south, :west]
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degree = degree / 90
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degree = -degree if direction == 'L'
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spin = dirs.find_index(facing) + degree
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spin -= 4 if spin > 3
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spin += 4 if spin < 0
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return dirs[spin]
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end
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def rotate (direction, degree, waypoint)
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degree = degree / 90
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degree.times do
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waypoint[:x_position], waypoint[:y_position] =
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waypoint[:y_position], (waypoint[:x_position])
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waypoint[:y_position] *= -1 if direction =='R'
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waypoint[:x_position] *= -1 if direction == 'L'
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end
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return waypoint
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end
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ship = {
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:facing => :east,
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:x_position => 0,
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:y_position => 0
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}
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waypoint = {
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:x_position => 10,
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:y_position => 1
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}
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directions = File.read('./input').split("\n")
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directions.each do |direction|
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instruction = direction[0]
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count = direction[1..-1].to_i
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p [instruction, count]
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case instruction
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when 'F'
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count.times do
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ship[:x_position] += waypoint[:x_position]
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ship[:y_position] += waypoint[:y_position]
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end
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when 'N'
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waypoint[:y_position] += count
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when 'S'
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waypoint[:y_position] -= count
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when 'E'
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waypoint[:x_position] += count
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when 'W'
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waypoint[:x_position] -= count
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when 'R','L'
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waypoint = rotate(instruction, count, waypoint)
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end
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pp ship
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end
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manhattan = ship[:x_position].abs + ship[:y_position].abs
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p manhattan
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#binding.pry
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