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2019: Day 15 Part 1

This commit is contained in:
Jeremy Kaplan 2019-12-15 12:49:30 -08:00
commit e81de93801
2 changed files with 515 additions and 0 deletions

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# frozen_string_literal: true
require 'forwardable'
module Intcode
def self.read(filename)
parse File.read(filename)
end
def self.parse(input)
parsed = input
.gsub(/^#.*$/, '')
.gsub('\s', '')
.split(',')
.map(&:to_i)
Program.new parsed
end
class Program
def initialize(mem)
@initial_state = mem
end
def as_memory
Memory.new(@initial_state.clone)
end
def run(&user_input)
Computer.new(as_memory).run(&user_input)
end
end
class Memory
extend Forwardable
def_delegator :@cells, :[]
def_delegator :@cells, :[]=
attr_accessor :relative_base
def initialize(cells)
@cells = cells
@relative_base = 0
end
def to_s
batch_size = 10
s = String.new
@cells.each_slice(batch_size).each_with_index do |batch, idx|
prefix = idx * batch_size
s << "#{prefix}: #{batch.join(' ')}\n"
end
s
end
def read(addr, mode)
# raise ArgumentError, "address out of range: #{addr}" if addr.negative? || addr >= @cells.length
return 0 if addr.negative? || addr >= @cells.length
case mode
when INDIRECT_MODE
read(@cells[addr], IMMEDIATE_MODE)
when IMMEDIATE_MODE
@cells[addr]
when RELATIVE_MODE
read(@cells[addr] + relative_base, IMMEDIATE_MODE)
else
raise ArgumentError, "unexpected mode: #{mode}"
end
end
def write(addr, mode, val)
raise ArgumentError, "address out of range: #{addr}" if addr.negative? || addr >= @cells.length
case mode
when INDIRECT_MODE
r = @cells[addr]
@cells[r] = val
when IMMEDIATE_MODE
raise ArgumentError, 'writes are not allowed in immediate mode'
@cells[addr]
when RELATIVE_MODE
r = @cells[addr] + relative_base
@cells[r] = val
else
raise ArgumentError, "unexpected mode: #{mode}"
end
end
end
INDIRECT_MODE = 0
IMMEDIATE_MODE = 1
RELATIVE_MODE = 2
class Computer
def initialize(mem, &block)
@mem = mem
@ip = 0
@input_block = block
end
def on_output(&block)
@output_block = block
end
def run
loop do
return if tick == :done_executing
end
end
def tick
opcode = operation(@mem[@ip])
case opcode
when 1
add!
nil
when 2
mul!
nil
when 3
input!(&@input_block)
nil
when 4
output!(&@output_block)
when 5
branch_if_not_zero!
nil
when 6
branch_if_zero!
nil
when 7
less_than!
nil
when 8
equal!
nil
when 9
move_relative_base!
nil
when 99
:done_executing
else
raise StandardError, "unexpected opcode: #{opcode}"
end
end
private
def add!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
@mem.write(@ip + 3, mode[2], a + b)
@ip += 4
end
def mul!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
@mem.write(@ip + 3, mode[2], a * b)
@ip += 4
end
def input!(&user_input)
mode = modes(@mem[@ip])
inp = input(&user_input)
@mem.write(@ip + 1, mode[0], inp)
@ip += 2
end
def output!(&user_output)
mode = modes(@mem[@ip])
output = @mem.read(@ip + 1, mode[0])
user_output.call output if block_given?
@ip += 2
output
end
def branch_if_not_zero!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
@ip = a.zero? ? @ip + 3 : b
end
def branch_if_zero!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
@ip = a.zero? ? b : @ip + 3
end
def less_than!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
val = a < b ? 1 : 0
@mem.write(@ip + 3, mode[2], val)
@ip += 4
end
def equal!
mode = modes(@mem[@ip])
a = @mem.read(@ip + 1, mode[0])
b = @mem.read(@ip + 2, mode[1])
val = a == b ? 1 : 0
@mem.write(@ip + 3, mode[2], val)
@ip += 4
end
def move_relative_base!
mode = modes(@mem[@ip])
delta = @mem.read(@ip + 1, mode[0])
@mem.relative_base += delta
@ip += 2
end
def input
if block_given?
inp = yield
raise "Invalid input: #{inp.inspect}" unless inp.is_a?(Numeric)
return inp
end
print 'input> '
gets.to_i
end
def operation(cell)
(cell % 100)
end
def modes(cell)
m = Hash.new(0)
(cell / 100).truncate.digits.each_with_index do |d, i|
m[i] = d
end
m
end
end
end

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# frozen_string_literal: true
require 'set'
require_relative 'intcode'
Cell = Struct.new(:x, :y) do
def north
Cell.new(x, y - 1)
end
def south
Cell.new(x, y + 1)
end
def west
Cell.new(x - 1, y)
end
def east
Cell.new(x + 1, y)
end
def neighbors
[north, south, west, east]
end
def direction_to(other)
dx = other.x - x
dy = other.y - y
if dy.negative?
:north
elsif dy.positive?
:south
elsif dx.negative?
:west
elsif dx.positive?
:east
end
end
end
class Map
def initialize
@grid = {}
end
def set_content!(cell, content)
@grid[cell] = content
end
def get(cell)
@grid[cell]
end
def printable(droid_position)
tl, br = corners(droid_position)
s = String.new
(tl.y..br.y).each do |y|
(tl.x..br.x).each do |x|
cell = Cell.new(x, y)
s << if cell == droid_position
'D'
else
char(cell)
end
end
s << "\n"
end
s
end
def goal
@grid.each_pair do |cell, content|
return cell if content == :oxygen
end
nil
end
private
def corners(droid_position)
min_x = max_x = droid_position.x
min_y = max_y = droid_position.y
@grid.keys.each do |p|
min_x = [min_x, p.x].min
min_y = [min_y, p.y].min
max_x = [max_x, p.x].max
max_y = [max_y, p.y].max
end
upper_left = Cell.new(min_x, min_y)
lower_right = Cell.new(max_x, max_y)
[upper_left, lower_right]
end
def char(cell)
content = get(cell)
case content
when :wall
'#'
when :open
'.'
when :oxygen
'G'
when nil
' '
else
raise StandardError, "unknown content: #{content}"
end
end
end
class Droid
def initialize(program, map)
@computer = Intcode::Computer.new(program.as_memory) { on_input }
@map = map
@direction = nil
@position = Cell.new(0, 0)
@mode = :exploration
@map.set_content!(@position, :open)
end
MOVEMENT_COMMANDS = { north: 1, south: 2, west: 3, east: 4 }.freeze
def on_input
MOVEMENT_COMMANDS.fetch(@direction)
end
def run
iterations = 0
loop do
result = step!
if (iterations % 100).zero?
print_state!
sleep 0.01
end
return result if result
iterations += 1
end
end
private
def step!
case @mode
when :exploration
step_exploration!
nil
when :pathfinding
step_pathfinding
end
end
def step_pathfinding
search(Cell.new(0, 0), @map.goal)
end
def step_exploration!
if @path.nil? || @path.length.zero? || @position == @path[-1] || blocked?(@path)
target = closest_unexplored_cell
if target.nil?
# Nothing left to see!
@mode = :pathfinding
return
end
@path = replan(target)
end
@direction = next_movement
status = next_output!
case status
when 0
set_content!(@direction, :wall)
# no movement
when 1
set_content!(@direction, :open)
move!(@direction)
when 2
set_content!(@direction, :oxygen)
move!(@direction)
else
raise StandardError, "unknown status: #{status}"
end
end
def next_movement
@path.shift if @position == @path[0]
target = @path[0]
@position.direction_to(target)
end
def blocked?(path)
path.any? do |cell|
@map.get(cell) == :wall
end
end
def closest_unexplored_cell
path = bfs(
@position,
->(cell) { cell.neighbors.reject { |c| @map.get(c) == :wall } },
->(cell) { @map.get(cell).nil? },
)
path.nil? ? nil : path[-1]
end
def replan(goal)
search(@position, goal)
end
def search(start, goal)
bfs(
start,
->(cell) { cell.neighbors.reject { |c| @map.get(c) == :wall } },
->(cell) { cell == goal },
)
end
def move!(direction)
@position = @position.send(direction)
@path.shift if @position == @path[0]
end
def next_output!
out = nil
out = @computer.tick until out
out
end
def set_content!(direction, content)
neighbor = @position.send(direction)
@map.set_content!(neighbor, content)
end
def print_state!
system 'clear'
puts @map.printable(@position)
end
end
def bfs(start, get_neighbors, is_goal)
queue = [[start]]
visited = Set.new
until queue.empty?
path = queue.shift
state = path[-1]
next if visited.include? state
visited << state
return path if is_goal.call(state)
children = get_neighbors.call(state).reject { |cell| visited.include? cell }
children.each do |child|
queue << path + [child]
end
end
nil
end
program = Intcode.read(File.join(__dir__, 'input'))
map = Map.new
droid = Droid.new(program, map)
path = droid.run
puts path.length - 1