Examples collection
/ P36 - Determine the prime factors of a given positive integer (2).
P36 - Determine the prime factors of a given positive integer (2).
Hint: The problem is similar to problem P13.
This was originally a blog post:
http://blogs.perl.org/users/ovid/2010/08/prime-factors-in-perl-6.html .
Specification
P36 (**) Determine the prime factors of a given positive integer (2).
Construct a list containing the prime factors and their multiplicity.
Example
> prime_factors_mult(315).perl.say
(3 => 2, 5 => 1, 7 => 1)
use v6;
constant PRIMES = grep { .is-prime }, 2 .. *;
sub prime-factors(Int $number-to-factor where * > 1 --> Hash) {
return { $number-to-factor => 1 } if $number-to-factor.is-prime;
my %factors;
my $number = $number-to-factor;
for PRIMES.cache -> $prime {
last if $prime ** 2 > $number;
while $number %% $prime {
%factors{$prime}++;
$number div= $prime;
}
}
%factors{$number}++ if $number != 1; # we have a prime left over
return %factors;
}
for 2, 17, 53, 90, 94, 200, 289, 62710561 -> $number {
say "Prime factors of $number are: {prime-factors($number).perl}";
}
# vim: expandtab shiftwidth=4 ft=perl6
See Also P04-topo.pl
P04 - Find the number of elements in a list.
P06-ajs.pl
P06 - Find out whether a list is a palindrome.
P06-topo.pl
P06 - Find out whether a list is a palindrome.
P08-eric256.pl
P08 - Eliminate consecutive duplicates of list elements.
P08-topo.pl
P08 - Eliminate consecutive duplicates of list elements.
P08-viklund.pl
P08 - Eliminate consecutive duplicates of list elements.
P09-rje.pl
P09 - Pack consecutive duplicates of list elements into sublists.
P09-scottp.pl
P09 - Pack consecutive duplicates of list elements into sublists.
P09-topo.pl
P09 - Pack consecutive duplicate elements of a list into sublists.
P09-unobe.pl
P09 - Pack consecutive duplicates of list elements into sublists.
P13-rhebus.pl
P13 - Run-length encoding of a list (direct solution).
P15-rhebus.pl
P15 - Replicate the elements of a list a given number of times.
P15-topo.pl
P15 - Replicate the elements of a list a given number of times.
P15-unobe.pl
P15 - Replicate the elements of a list a given number of times.
P17-topo.pl
P17 - Split a list into two parts; the length of the first part is given.
P17-unobe.pl
P17 - Split a list into two parts; the length of the first part is given.
P18-topo.pl
P18 - Extract a slice from a list. Indices start at 1.
P21-scottp.pl
P21 - Insert an element at a given position into an array.
P21-topo.pl
P21 - Insert an element at a given position into a list.
P22-scottp.pl
P22 - Create a list containing all integers within a given range.
P22-topo.pl
P22 - Create a list containing all integers within a given range.
P23-topo.pl
P23 - Extract a given number of randomly selected elements from a list.
P24-topo.pl
P24 - Draw N different random numbers from the set 1..M.
P25-topo.pl
P25 - Generate a random permutation of the elements of a list.
P26-topo.pl
P26 - Generate the combinations of k distinct objects chosen from the n elements of a list.
P31-rhebus.pl
P31 - Determine whether a given integer number is prime.
P32-rhebus.pl
P32 - Determine the greatest common divisor of two positive integer
P33-rhebus.pl
P33 - Determine whether two positive integer numbers are coprime.
P35-rhebus.pl
P35 - Determine the prime factors of a given positive integer.
P36-rhebus.pl
P36 - Determine the prime factors of a given positive integer (2).
P37-rhebus.pl
P37 - Calculate Euler's totient function phi(m) (improved).
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/ P36 - Determine the prime factors of a given positive integer (2).
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