use v6;

my %ball = map { $_ => 1; } 1..12;
Modify_Ball( %ball );

say ~Find_Odd_Ball( %ball );
say %ball.perl;

sub Find_Odd_Ball (%ball) {
    my $r_1 = ([+] %ball{1..4}) <=> ([+] %ball{5..8});
    given $r_1 {
        when 0  {
            my $r_2 = ([+] %ball{9,10}) <=> ([+] %ball{1,11});
            given $r_2 {
                when 0  { return (12, %ball{12} <=> %ball{1}) }
                default {
                    my $r_3 = %ball{9} <=> %ball{10}; 
                    given $r_3 {
                        when  0 { return (11, $r_2 * -1) }
                        default { return $r_2 == $r_3 ?? (9, $r_3) :: (10, $r_3 * -1) }
                    }
                }
            }
        }
        default {
            my $r_2 = ([+] %ball{1,2,5}) <=> ([+] %ball{3,6,10});
            if ! $r_2 {
                my $r_3 = %ball{7} <=> %ball{8};
                given $r_3 {
                    when  0 { return (4, $r_1) }
                    default { return $r_1 == $r_3 ?? (8, $r_3 * -1) :: (7, $r_3) }
                }
            }
            return %ball{3} == %ball{10} ?? (5, $r_2) :: (3, $r_1) if $r_1 ne $r_2;
            my $r_3 = %ball{1} <=> %ball{2};
            given $r_3 {
                when  0 { return (6, $r_2 * -1) }
                default { return $r_2 == $r_3 ?? (1, $r_2) :: (2, $r_2) }
            }
        }
    }
}

sub Modify_Ball( %ball is rw ) returns Void {
    my $num = int( rand 12 ) + 1; 
    my $adj = .1 * (int( rand 2 ) ?? 1 :: -1);
    %ball{$num} += $adj;
}