p6.p6

#!/usr/bin/env perl6

my int @instructions = 'day_05.input'.IO.lines.map: *.Int;
my int $index = 0;
my int $stop = @instructions.elems;
my int $iterations = 0;
my int $jump;

while $index < $stop {
    $jump = @instructions.AT-POS: $index;

    $jump >= 3 ?? --@instructions.AT-POS: $index
               !! ++@instructions.AT-POS: $index;

    $index = $index + $jump;
    ++$iterations;
}

say $iterations;