Day 11

1 files changed, 164 insertions, 0 deletions

diff --git a/day11/part1 b/day11/part1
new file mode 100755
index 0000000..4962e2e
--- /dev/null
+++ b/day11/part1
@@ -0,0 +1,164 @@
+#!/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
+
+def turn(d, t)
+  if t.zero? then
+    case d
+    when [0, -1]
+      [-1, 0]
+    when [-1, 0]
+      [0, 1]
+    when [0, 1]
+      [1, 0]
+    when [1, 0]
+      [0, -1]
+    end
+  else
+    case d
+    when [0, -1]
+      [1, 0]
+    when [-1, 0]
+      [0, -1]
+    when [0, 1]
+      [-1, 0]
+    when [1, 0]
+      [0, 1]
+    end
+  end
+end
+
+def move(l, d)
+  [l[0] + d[0], l[1] + d[1]]
+end
+
+input = $stdin.readlines[0].strip.split(",").map(&:to_i)
+
+m = Machine.new(input)
+grid = Hash.new{0}
+
+l = [0, 0]
+d = [0, -1]
+loop do
+  m.buffer_input(grid[l])
+  until m.halt? || m.buffered_output.length == 2 do
+    m.step
+  end
+  if m.halt? then
+    break
+  else
+    p, t = m.buffered_output(true)
+    grid[l] = p
+    d = turn(d, t)
+    l = move(l, d)
+  end
+end
+
+puts grid.keys.count