/* 

  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 and 3b.pi here are some other versions of part 1 and 
  part 2. Part 2 is quite neater than in 3.pi and 3b.pi

  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.

/*
  Part 1 and part 2 combined.

  Hyperfine
  Benchmark 1: picat -g go 3c.pi
    Time (mean ± σ):      37.6 ms ±   7.7 ms    [User: 20.4 ms, System: 17.1 ms]
    Range (min … max):    18.5 ms …  49.0 ms    55 runs

*/
go =>
  Chars = read_file_chars("3.txt"),
  % Part 1
  X = regex_find_all("mul\\((\\d+?),(\\d+?)\\)",Chars),
  [A.to_int*B.to_int : [A,B] in X].sum.println(),
  % Part 2
  s(X,true,0,S), % part2b
  println(S).

/*
  Part 1
  Hyperfine

  Benchmark 1: picat -g part1 3c.pi
    Time (mean ± σ):      36.9 ms ±   5.2 ms    [User: 19.0 ms, System: 17.8 ms]
    Range (min … max):    22.4 ms …  45.4 ms    63 runs

*/
part1 =>
  X = regex_find_all("mul\\((\\d+?),(\\d+?)\\)",read_file_chars("3.txt")),
  [A.to_int*B.to_int : [A,B] in X].sum.println().


/* 
  Part 2

  This is a neater imperative variant compared to the one in 3.pi and 3b.pi

  Hyperfine
  Benchmark 1: picat -g part2 3c.pi
    Time (mean ± σ):      38.4 ms ±   6.0 ms    [User: 20.8 ms, System: 17.5 ms]
    Range (min … max):    22.5 ms …  49.2 ms    57 runs


*/
part2 => 
  File = "3.txt",
  X = regex_find_all("mul\\((\\d+?),(\\d+?)\\)|do\\(\\)|don't\\(",read_file_chars(File)),
  State = true,
  S = 0,
  foreach(P in X)
    if P == "do()" then
      State := true
    elseif P == "don't(" then
      State := false
    else
      if State then
        S := S + P.map(to_int).prod
      end
    end,
  end,
  println(S).

/*
  Part 2 b
  Variant using recursion.

  Hyperfine
  Benchmark 1: picat -g part2b 3c.pi
    Time (mean ± σ):      35.7 ms ±   7.5 ms    [User: 18.5 ms, System: 17.1 ms]
    Range (min … max):    18.4 ms …  49.8 ms    52 runs

*/
part2b => 
  File = "3.txt",
  X = regex_find_all("mul\\((\\d+?),(\\d+?)\\)|do\\(\\)|don't\\(",read_file_chars(File)),
  s(X,true,0,S),
  println(S).
  
s([],Status,S,S).
s([P|Xs],true,S0,S) :-
  ( P.len==2 -> s(Xs,true,S0+P.map(to_int).prod,S) ;
    P == "don't(" -> s(Xs,false,S0,S) ;
    s(Xs,true,S0,S)
  ).
s([P|Xs],false,S0,S) :-
  ( P == "do()" -> s(Xs,true,S0,S) ;
    s(Xs,false,S0,S)
  ).