Advent-of-Code/AdventOfCode-2020
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Clean up day 12.

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This commit is contained in:
Danila Fedorin 2020-12-12 01:44:04 -08:00
parent 5f231facc6
commit 8459219e60
1 changed files with 15 additions and 32 deletions
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47
day12.cr
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@ -1,4 +1,5 @@
require "advent" require "advent"
DISTS = [{1, 0}, {0, 1}, {-1, 0}, {0, -1}]
INPUT = input(2020, 12).lines.map do |l| INPUT = input(2020, 12).lines.map do |l|
{l[0], l[1..].to_i32} {l[0], l[1..].to_i32}
end end
@ -8,21 +9,14 @@ def part1(input)
angle = 0 angle = 0
input.each do |c, n| input.each do |c, n|
case c case c
when 'N' when 'N' then pos = pos.add({0, n})
pos = pos.add({0, n}) when 'S' then pos = pos.add({0, -n})
when 'S' when 'E' then pos = pos.add({n, 0})
pos = pos.add({0, -n}) when 'W' then pos = pos.add({-n, 0})
when 'E' when 'L' then angle = (angle + n) % 360
pos = pos.add({n, 0}) when 'R' then angle = (angle + (360-n)) % 360
when 'W'
pos = pos.add({-n, 0})
when 'L'
angle = (angle + n) % 360
when 'R'
angle = (angle + (360-n)) % 360
when 'F' when 'F'
dists = [{1, 0}, {0, 1}, {-1, 0}, {0, -1}] dx, dy = DISTS[angle//90]
dx, dy = dists[angle//90]
pos = pos.add({dx * n, dy * n}) pos = pos.add({dx * n, dy * n})
end end
end end
@ -35,24 +29,13 @@ def part2(input)
angle = 0 angle = 0
input.each do |c, n| input.each do |c, n|
case c case c
when 'N' when 'N' then pos = pos.add({0, n})
pos = pos.add({0, n}) when 'S' then pos = pos.add({0, -n})
when 'S' when 'E' then pos = pos.add({n, 0})
pos = pos.add({0, -n}) when 'W' then pos = pos.add({-n, 0})
when 'E' when 'L' then (n//90).times { pos = {-pos[1], pos[0]} }
pos = pos.add({n, 0}) when 'R' then (n//90).times { pos = {pos[1], -pos[0]} }
when 'W' when 'F' then spos = spos.add({pos[0] * n, pos[1]*n})
pos = pos.add({-n, 0})
when 'L'
(n//90).times do
pos = {-pos[1], pos[0]}
end
when 'R'
(n//90).times do
pos = {pos[1], -pos[0]}
end
when 'F'
spos = spos.add({pos[0] * n, pos[1]*n})
end end
end end
spos.map(&.abs).sum spos.map(&.abs).sum