AoC2020 Day 15

my @n = 20,9,11,0,1,2;
my %l; %l{@n} = ^@n;

for @n.end..29_999_999 -> $t {
    if $t == %l{@n[$t]} { # first time spoken
        @n[$t+1] = 0;
    }
    else {
        @n[$t+1] = $t - %l{@n[$t]};
        %l{@n[$t]} = $t;
    }
    %l{@n[$t+1]} //= $t+1;
}

say "Part One: " ~ @n[2019];
say "Part Two: " ~ @n[29_999_999];