#!/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 puts m.buffered_output.map(&:chr).join