AOC2019day7part1

7-1.sh

#!/bin/bash

set -eu

getval() {
  case $1 in
    0) echo "${ram[$2]}" ;;
    1) echo "$2" ;;
  esac
}

jmpt() {
  local addrmode=$1
  local arg=$(getval "${addrmode:0:1}" "$2")
  local dest=$(getval "${addrmode:1:1}" "$3")
  if [ "$arg" -ne 0 ]; then
    pc=$dest
  else
    pc=$((pc+2))
  fi
}

jmpf() {
  local addrmode=$1
  local arg=$(getval "${addrmode:0:1}" "$2")
  local dest=$(getval "${addrmode:1:1}" "$3")
  if [ "$arg" -eq 0 ]; then
    pc=$dest
  else
    pc=$((pc+2))
  fi
}

add() {
  local addrmode=$1
  local src1=$(getval "${addrmode:0:1}" "$2")
  local src2=$(getval "${addrmode:1:1}" "$3")
  local dest=$4
  ram[$dest]=$((src1 + src2))
  pc=$((pc+3))
}

mul() {
  local addrmode=$1
  local src1=$(getval "${addrmode:0:1}" "$2")
  local src2=$(getval "${addrmode:1:1}" "$3")
  local dest=$4
  ram[$dest]=$((src1 * src2))
  pc=$((pc+3))
}

cmpl() {
  local addrmode=$1
  local src1=$(getval "${addrmode:0:1}" "$2")
  local src2=$(getval "${addrmode:1:1}" "$3")
  local dest=$4
  if [ "$src1" -lt "$src2" ]; then
    ans=1
  else
    ans=0
  fi
  ram[$dest]=$ans
  pc=$((pc+3))
}

cmpe() {
  local addrmode=$1
  local src1=$(getval "${addrmode:0:1}" "$2")
  local src2=$(getval "${addrmode:1:1}" "$3")
  local dest=$4
  if [ "$src1" -eq "$src2" ]; then
    local ans=1
  else
    local ans=0
  fi
  ram[$dest]=$ans
  pc=$((pc+3))
}

inb() {
  local addrmode=$1
  local dest=$2
  ram[$dest]=${inputs[0]}
  inputs="${inputs[@]:1}"
  pc=$((pc+1))
}

outb() {
  local addrmode=$1
  local src=$(getval "${addrmode:0:1}" "$2")
  echo "$src"
  pc=$((pc+1))
}

gdb() {
  echo -ne "$pc"\\t >&2
  seq 0 15 | xargs | tr \  \\t >&2
  for addr in $(seq 0 16 "${#ram[@]}"); do
     echo "$addr: ${ram[@]:$addr:16}" | tr \  \\t >&2
  done
}

run() {
  inputs=("$@")
  [ -z "${DEBUG:-}" ] || echo "program start: ${inputs[@]}" >&2
  pc=0
  ram=("${program[@]}")
  while true; do
    local opcode=$(printf %04d "${ram[$pc]}")
    local addrmode=${opcode: -3:1}${opcode: -4:1}
    [ -z "${DEBUG:-}" ] || gdb
    pc=$((pc+1))
    case "${opcode: -2}" in
      01) add  "$addrmode" "${ram[@]:$pc:3}" ;;
      02) mul  "$addrmode" "${ram[@]:$pc:3}" ;;
      03) inb  "$addrmode" "${ram[@]:$pc:1}" ;;
      04) outb "$addrmode" "${ram[@]:$pc:1}" ;;
      05) jmpt "$addrmode" "${ram[@]:$pc:2}" ;;
      06) jmpf "$addrmode" "${ram[@]:$pc:2}" ;;
      07) cmpl "$addrmode" "${ram[@]:$pc:3}" ;;
      08) cmpe "$addrmode" "${ram[@]:$pc:3}" ;;
      99) break ;;
      *)
        echo "Unknown opcode $opcode at $pc" >&2
        return 1
      ;;
    esac
  done
}

IFS=, read -r -a program < "$1"

highestoutput=0
for phases in {0,1,2,3,4},{0,1,2,3,4},{0,1,2,3,4},{0,1,2,3,4},{0,1,2,3,4}; do
  IFS=, read -r -a phasearray <<<"$phases"
  if [ "$(xargs -n1 echo <<<"${phasearray[@]}" | sort -u)" != "$(xargs -n1 echo <<<"${phasearray[@]}" | sort)" ]; then
    continue
  fi
  acc=0
  for phase in "${phasearray[@]}"; do
    acc=$(run "$phase" "$acc")
  done
  if [ "$acc" -gt "$highestoutput" ]; then
    highestoutput=$acc
  fi
done
echo "$highestoutput"