/* 

  Advent of Code 2024 in Picat.

  Problem 3
  https://adventofcode.com/2024/day/3

  Note: This program uses my regex module: https://github.com/hakank/picat_regex

  Compared to 3.pi, this an alternative (and a little neater) version of part2/0. 
  part1/0 is the same.

  This program was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/

import regex.
import aoc_utils.

main => go.

/*
  Hyperfine

  Benchmark 1: picat -g go 3b.pi
    Time (mean ± σ):      37.3 ms ±   8.2 ms    [User: 22.7 ms, System: 14.4 ms]
    Range (min … max):    14.6 ms …  49.9 ms    64 runs

*/
go =>
  part1,
  part2,
  nl.

/*
  Hyperfine

  Benchmark 1: picat -g part1 3b.pi
    Time (mean ± σ):      37.8 ms ±   5.7 ms    [User: 19.7 ms, System: 17.6 ms]
    Range (min … max):    23.9 ms …  48.9 ms    60 runs
 

*/
part1 => 
  println(find_all_mul(read_file_chars("3.txt")).sum).


/* 
  Hyperfine
 
  Benchmark 1: picat -g part2 3b.pi
    Time (mean ± σ):      37.1 ms ±   6.6 ms    [User: 20.7 ms, System: 15.9 ms]
    Range (min … max):    18.8 ms …  50.0 ms    67 runs

*/

parse2([],Status,Mul) = [Status,Mul].

parse2(L,true,Mul0) = [Status,Mul] =>
  ( append(Valid,"don't()",Rest,L) ->
     Mul1 = find_all_mul(Valid),
     [Status,Mul] = parse2(Rest,false,Mul1++Mul0)
    ;
     Mul1 = find_all_mul(L),
     [Status,Mul] = parse2("",true,Mul1++Mul0)
  ).
  
parse2(L,false,Mul0) = [Status,Mul] =>
  ( append(_A,"do()",Rest,L) ->
     [Status,Mul] = parse2(Rest,true,Mul0)
    ;
     [Status,Mul] = parse2("",false,Mul0)
  ).


part2 => 
  File = "3.txt",
  Lines = read_file_lines(File),
  Sum = 0,
  Status = true,
  foreach(Line in Lines)
    [Status1,Mul] = parse2(Line,Status,[]),
    Status := Status1,
    Sum := Sum + Mul.sum
  end,
  println(Sum),
  nl.


% Using regex
find_all_mul(L) = [A.to_int*B.to_int : [A,B] in regex_find_all("mul\\((\\d+?),(\\d+?)\\)",L)].