#!/usr/bin/env bash
unset PATH
readonly PATH
source ./utils/main.sh
source ./utils/array.sh
NUM_JOBS="\j"

solve() {
  local part="$1" target="$2" curr="$3" rest=("${@:4}")

  ((${#rest[@]} == 0)) && {
    ((curr == target)) && echo "$target" && return 0
    return 1
  }

  solve "$part" "$target" "$((curr + rest[0]))" "${rest[@]:1}" ||
    solve "$part" "$target" "$((curr * rest[0]))" "${rest[@]:1}" || {
    ((part == 1)) && return 1
    solve "$part" "$target" "${curr}${rest[0]}" "${rest[@]:1}"
  }
}

do_part() {
  local part="$1" result=0

  while read -r num; do
    ((result += num))
  done < <(
    while read -r line; do
      while ((${NUM_JOBS@P} >= 16)); do wait -n; done
      {
        local nums=() target
        read -ra nums <<<"${line#*: }"
        target="${line%:*}"
        solve "$part" "$target" "${nums[@]}"
      } &
    done
    wait
  )

  printf '%d' "$result"
}

p1() {
  do_part 1 <<<"$1"
}

p2() {
  do_part 2 <<<"$1"
}

main "$@"