Largest palindrome product: Difference between revisions

Line 75:

=={{header|Raku}}==

<lang perl6>use ~~Prime~~::~~Factor~~;

<lang perl6>use Inline::Perl5;

.say for (1..~~11).hyper(:1batch~~).map: {.&lpp};

my $p5 = Inline::Perl5.new();

$p5.use: 'ntheory';

my &divisors = $p5.run('sub { ntheory::divisors $_[0] }');

.say for (2..12).map: {.&lpp};

multi lpp ($oom where {$_ +& 1}) { # even number of multiplicand digits

my $f = ~~+(9 x (~~$oom + ~~1))~~;

multi lpp ($oom where {!($_ +& 1)}) { # even number of multiplicand digits

my $o = (1 + $oom) / 2;

my $~~pal~~ = +(9 x $~~o ~ 0 x $o * 2 ~ 9 x $o~~);

my $f = +(9 x $oom);

my $o = $oom / 2;

sprintf "Largest palindromic product of two %2d-digit integers: %d × %d = %d", $oom ~~+ 1~~, $pal div $f, $f, $pal

my $pal = +(9 x $o ~ 0 x $oom ~ 9 x $o);

sprintf "Largest palindromic product of two %2d-digit integers: %d × %d = %d", $oom, $pal div $f, $f, $pal

}

multi lpp ($oom where {$_ +^ 1}) { # odd number of multiplicand digits

multi lpp ($oom where {$_ +& 1}) { # odd number of multiplicand digits

my $p;

(+(1 ~ (0 x $oom)) .. +(9 ~ (9 x $oom))).reverse.map({ +($_ ~ .flip) }).map: -> $pal {

(+(1 ~ (0 x ($oom - 1))) .. +(9 ~ (9 x ($oom - 1)))).reverse.map({ +($_ ~ .flip) }).map: -> $pal {

for my @factors = $pal.~~&divisors~~.grep({.chars == ($oom ~~+ 1)~~}).sort(-*) {

for my @factors = divisors("$pal")».Int.grep({ .chars == $oom }).sort( -* ) {

next unless $pal div $_ ∈ @factors;

$p = sprintf("Largest palindromic product of two %2d-digit integers: %d × %d = %d", $oom ~~+ 1~~, $pal div $_, $_, $pal) ~~and last~~;

$p = sprintf("Largest palindromic product of two %2d-digit integers: %d × %d = %d", $oom, $pal div $_, $_, $pal);

last;

}

last if $p;