66 lines
1.9 KiB
Ruby
66 lines
1.9 KiB
Ruby
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#!/usr/bin/env ruby
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# frozen_string_literal: true
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require 'pry'
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def diagonal(array, x, y)
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x_limit = array.size - 1 - x
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y_limit = array[0].size - 1 - y
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limit = x_limit < y_limit ? x_limit : y_limit
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(0..limit).map { |i| array[x + i][y + i] }
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end
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def diagonal2(array, x, y)
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x_limit = array.size - 1 - x
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y_limit = y
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limit = x_limit < y_limit ? x_limit : y_limit
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(0..limit).map { |i| array[x + i][y - i] }
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end
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def xmas_slice(array, x, y)
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out = []
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out.append(array[x][y] + array[x + 1][y + 1] + array[x + 2][y + 2])
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out.append(array[x][y + 2] + array[x + 1][y + 1] + array[x + 2][y])
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(out[0].match?(/MAS|SAM/) and out[1].match?(/MAS|SAM/))
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end
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# input = 'MMMSXXMASM
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# MSAMXMSMSA
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# AMXSXMAAMM
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# MSAMASMSMX
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# XMASAMXAMM
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# XXAMMXXAMA
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# SMSMSASXSS
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# SAXAMASAAA
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# MAMMMXMMMM
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# MXMXAXMASX'.split
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input = File.readlines('./input').map(&:strip)
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vertical = input.map(&:chars).transpose.map(&:join)
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d1_coords = (0..(input.size - 1)).map { [0, _1] }
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d2_coords = d1_coords.dup
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d1_coords += (1..(input.size - 1)).map { [_1, 0] }
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d2_coords += (1..(input.size - 1)).map { [_1, (input.size - 1)] }
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diagonal = d1_coords.map { |x, y| diagonal(input, x, y) }.map(&:join)
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diagonal2 = d2_coords.map { |x, y| diagonal2(input, x, y) }.map(&:join)
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# binding.pry
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count = 0
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count += input.map { |line| line.scan('XMAS') }.flatten.length
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count += input.map { |line| line.scan('SAMX') }.flatten.length
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count += vertical.map { |line| line.scan('XMAS') }.flatten.length
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count += vertical.map { |line| line.scan('SAMX') }.flatten.length
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count += diagonal.map { |line| line.scan('XMAS') }.flatten.length
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count += diagonal.map { |line| line.scan('SAMX') }.flatten.length
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count += diagonal2.map { |line| line.scan('XMAS') }.flatten.length
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count += diagonal2.map { |line| line.scan('SAMX') }.flatten.length
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# binding.pry
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puts count
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# Part 2
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p2 = (0..input.size - 3).map { |x| (0..input.size - 3).map { |y| xmas_slice(input, x, y) } }.flatten.count(true)
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puts p2
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