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class Pos
def initialize(x = 0, y = 0)
@x = x
@y = y
end
attr_reader :x, :y
def move(dir)
case dir
when "U"
@y += 1
when "D"
@y -= 1
when "R"
@x += 1
when "L"
@x -= 1
end
end
def follow(head)
if head.x == @x - 2 && head.y == @y + 2
@x -= 1
@y += 1
elsif head.x == @x - 1 && head.y == @y + 2
@x -= 1
@y += 1
elsif head.x == @x && head.y == @y + 2
@y += 1
elsif head.x == @x + 1 && head.y == @y + 2
@x += 1
@y += 1
elsif head.x == @x + 2 && head.y == @y + 2
@x += 1
@y += 1
elsif head.x == @x + 2 && head.y == @y + 1
@x += 1
@y += 1
elsif head.x == @x + 2 && head.y == @y
@x += 1
elsif head.x == @x + 2 && head.y == @y - 1
@x += 1
@y -= 1
elsif head.x == @x + 2 && head.y == @y - 2
@x += 1
@y -= 1
elsif head.x == @x + 1 && head.y == @y - 2
@x += 1
@y -= 1
elsif head.x == @x && head.y == @y - 2
@y -= 1
elsif head.x == @x - 1 && head.y == @y - 2
@x -= 1
@y -= 1
elsif head.x == @x - 2 && head.y == @y - 2
@x -= 1
@y -= 1
elsif head.x == @x - 2 && head.y == @y - 1
@x -= 1
@y -= 1
elsif head.x == @x - 2 && head.y == @y
@x -= 1
elsif head.x == @x - 2 && head.y == @y + 1
@x -= 1
@y += 1
end
end
def coord
[@x, @y]
end
end
moves = $stdin.readlines.map(&:strip).map(&:split)
rope = Array.new(10) { Pos.new }
visited = [rope[-1].coord]
moves.each do |dir, dist|
dist.to_i.times do
rope[0].move(dir)
(rope.length - 1).times do |i|
rope[i+1].follow(rope[i])
end
visited << rope[-1].coord
end
end
puts visited.uniq.count
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