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2022 Day 9 part 2

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Sven Weidauer 2022-12-10 17:16:13 +01:00
parent 6b96700e2e
commit 400efd5802
1 changed files with 30 additions and 22 deletions
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52
2022/day9.rb
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@ -4,36 +4,44 @@ def moveStep(dx, dy)
$headX += dx $headX += dx
$headY += dy $headY += dy
dx = $headX - $tailX (curX, curY) = [$headX, $headY]
dy = $headY - $tailY
case [dx.abs, dy.abs] $tail.each_index { |index|
when [0, 0], [1, 1], [1, 0], [0, 1] then (tailX, tailY) = $tail[index]
when [2, 0], [0, 2], [2, 2] then
$tailX += dx <=> 0
$tailY += dy <=> 0
when [2, 1] then
$tailX += dx <=> 0
$tailY += dy <=> 0
when [1, 2] then
$tailX += dx <=> 0
$tailY += dy <=> 0
else
puts "Unknown: (#{dx}, #{dy})"
raise
end
$tailPositions.add [$tailX, $tailY] dx = curX - tailX
dy = curY - tailY
case [dx.abs, dy.abs]
when [0, 0], [1, 1], [1, 0], [0, 1] then
# Stay the same
when [2, 0], [0, 2], [2, 2] then
tailX += dx <=> 0
tailY += dy <=> 0
when [2, 1] then
tailX += dx <=> 0
tailY += dy <=> 0
when [1, 2] then
tailX += dx <=> 0
tailY += dy <=> 0
else
puts "Unknown: (#{dx}, #{dy})"
raise
end
(curX, curY) = $tail[index] = [tailX, tailY]
}
$tailPositions.add [curX, curY]
end end
def run count def run count
$headX = 0 $headX = 0
$headY = 0 $headY = 0
$tailX = 0
$tailY = 0
$tail = [[$headX, $headY]] * (count - 1)
$tailPositions = Set[[$headX, $headY]] $tailPositions = Set[[$headX, $headY]]
for line in File.readlines('day9.input') for line in File.readlines('day9.input')
@ -60,5 +68,5 @@ def run count
end end
puts "Part 1: #{run(2)}" puts "Part 1: #{run(2)}"
puts "Part 2: #{run(10)}"