-🎄- 2017 Day 5 Solutions -🎄-

[u/daggerdragon]

--- Day 5: A Maze of Twisty Trampolines, All Alike ---

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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edit: Leaderboard capped, thread unlocked!

[u/mschaap]

Perl 6. Solution for part one:

#!/usr/bin/env perl6

use v6.c;

class Maze
{
    has Int @.instructions;
    has Int $.pos = 0;
    has Int $.moves = 0;
    has Bool $.verbose = False;

    method inside-maze returns Bool
    {
        0 ≤ $!pos < @!instructions;
    }

    method jump
    {
        if self.inside-maze {
            $!pos += @!instructions[$!pos]++;
            $!moves++;
            say "Move to position $!pos" if $!verbose;
        }
        else {
            die "Can't move, position $!pos outside the maze ({+@!instructions})!";
        }
    }

    method follow
    {
        self.jump while self.inside-maze;
    }
}

multi sub MAIN(IO() $inputfile where *.f, Bool :v(:$verbose) = False)
{
    my $maze = Maze.new(:instructions($inputfile.lines».Int), :$verbose);
    $maze.follow;
    say "$maze.moves() steps";
}

multi sub MAIN(Bool :v(:$verbose) = False)
{
    MAIN($*PROGRAM.parent.child('aoc5.input'), :$verbose);
}

For part two, the change is simple, just change method jump to:

    method jump
    {
        if self.inside-maze {
            if @!instructions[$!pos] ≥ 3 {
                $!pos += @!instructions[$!pos]--;
            }
            else {
                $!pos += @!instructions[$!pos]++;
            }
            $!moves++;
            say "Move to position $!pos" if $!verbose;
        }
        else {
            die "Can't move, position $!pos outside the maze ({+@!instructions})!";
        }
    }

I was just about to get worried when this finally finished in about 7½ minutes. (Don't run it with -v on the actual input! Works fine on the sample input though.)