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|
#!/usr/bin/env ruby
class Machine
def initialize(starting_memory = [])
@mem = starting_memory
@pc = 0
@halt = false
@buffered_input = []
@buffered_output = []
@relative_base = 0
end
def mem(start = 0, len = @mem.length)
@mem[start...(start + len)]
end
def halt!
@halt = true
end
def halt?
@halt
end
def buffer_input(x)
if x.is_a?(Array) then
@buffered_input += x
else
@buffered_input.push(x)
end
end
def buffered_output(flush = false)
t = @buffered_output
@buffered_output = [] if flush
t
end
def step
return if halt?
opcode = @mem[@pc] % 100
if opcode == 99 then
halt!
@pc += 1
return
end
p3, p2, p1 = ("%03d" % (@mem[@pc] / 100)).chars
l1w, l1r = get(p1, 1)
l2w, l2r = get(p2, 2) if [1,2,5,6,7,8].include?(opcode)
l3w, l3r = get(p3, 3) if [1,2,7,8].include?(opcode)
case opcode
when 1
@mem[l3w] = l1r + l2r
@pc += 4
when 2
@mem[l3w] = l1r * l2r
@pc += 4
when 3
@mem[l1w] = @buffered_input.shift
@pc += 2
when 4
@buffered_output.push(l1r)
@pc += 2
when 5
@pc = (l1r != 0 ? l2r : @pc + 3)
when 6
@pc = (l1r == 0 ? l2r : @pc + 3)
when 7
@mem[l3w] = (l1r < l2r ? 1 : 0)
@pc += 4
when 8
@mem[l3w] = (l1r == l2r ? 1 : 0)
@pc += 4
when 9
@relative_base += l1r
@pc += 2
end
end
def run
until halt? do
step
end
end
private
def get(p, a)
w = case p
when "0"
@mem[@pc + a]
when "2"
@relative_base + @mem[@pc + a]
end
r = case p
when "0"
@mem[@mem[@pc + a]]
when "1"
@mem[@pc + a]
when "2"
@mem[@relative_base + @mem[@pc + a]]
end
[w, r || 0]
end
end
input = $stdin.readlines[0].strip.split(",").map(&:to_i)
m = Machine.new(input)
m.run
grid = m.buffered_output.map(&:chr).join.lines.map(&:strip).map(&:chars).reject(&:empty?)
scaffs = []
x = 0
y = 0
d = 0
grid.length.times do |r|
grid[0].length.times do |c|
scaffs << [c, r] unless grid[r][c] == "."
if %w(< ^ > v).include?(grid[r][c]) then
x = c
y = r
d = %w(< ^ > v).index(grid[r][c])
end
end
end
def path_end?(x, y, scaffs)
c = 0
c += 1 if scaffs.include?([x-1, y])
c += 1 if scaffs.include?([x+1, y])
c += 1 if scaffs.include?([x, y-1])
c += 1 if scaffs.include?([x, y+1])
return c == 1
end
def count(x, y, d, scaffs)
c = 0
case d
when 0
loop do
break unless scaffs.include?([x-1, y])
c += 1
x -= 1
end
when 1
loop do
break unless scaffs.include?([x, y-1])
c += 1
y -= 1
end
when 2
loop do
break unless scaffs.include?([x+1, y])
c += 1
x += 1
end
when 3
loop do
break unless scaffs.include?([x, y+1])
c += 1
y += 1
end
end
return x, y, c
end
def turn(x, y, d, scaffs)
d = (d + 1) % 4
case d
when 0
return d, "R" if scaffs.include?([x-1, y])
when 1
return d, "R" if scaffs.include?([x, y-1])
when 2
return d, "R" if scaffs.include?([x+1, y])
when 3
return d, "R" if scaffs.include?([x, y+1])
end
d = (d + 2) % 4
return d, "L"
end
def find_start(x, y, d, scaffs)
t = 0
loop do
case d
when 0
return d, t if scaffs.include?([x-1, y])
when 1
return d, t if scaffs.include?([x, y-1])
when 2
return d, t if scaffs.include?([x+1, y])
when 3
return d, t if scaffs.include?([x, y+1])
end
d = (d + 1) % 4
t += 1
end
end
path = []
d, t = find_start(x, y, d, scaffs)
case t
when 1
path << "R"
when 2
path << "R"
path << "R"
when 3
path << "L"
end
loop do
x, y, c = count(x, y, d, scaffs)
path << c
break if path_end?(x, y, scaffs)
d, t = turn(x, y, d, scaffs)
path << t
end
p path
|
