Mercurial > repos > other > adventofcode2023
annotate day1.rb @ 39:0e17e4bd97a9 default tip
Rewrite as four-dimensional route finding
The grid isn't just a 2D grid. The constraints make it 4D:
* X
* Y
* Last direction
* Number of steps in that direction
By tracking all four dimensions, we can find the shortest route
for _all_ combinations of the constraint. Previously, we were dropping
routes that were currently longer but ended up shorter because
they could take subsequent steps that other routes couldn't.
author | IBBoard <dev@ibboard.co.uk> |
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date | Sun, 22 Sep 2024 11:30:53 +0100 |
parents | 76cc43966538 |
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0
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1 #! /usr/bin/env ruby |
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2 |
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3 if ARGV.length != 1 |
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4 abort("Incorrect arguments - pass a single file") |
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5 elsif not File.exist? (ARGV[0]) |
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6 abort ("File #{ARGV[0]} did not exist") |
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7 end |
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8 |
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9 file = ARGV[0] |
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10 sum = 0 |
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11 File.open(file, "r").each_line do |line| |
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12 match = /^[^0-9]*([0-9]).*?(([0-9])[^0-9]*)?$/.match(line) |
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13 if match |
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14 first_num = match[1].to_i |
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15 second_num = match[3].nil? ? first_num : match[3].to_i |
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16 sum += (first_num * 10) + second_num |
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17 end |
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18 end |
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19 |
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20 puts sum |