This is my 46th week participating into the weekly challenge.
TASK #1 › Prime Sum
Submitted by: Mohammad S Anwar
Reviewed by: Ryan Thompson
You are given a number $N. Write a script to find the minimum number of prime numbers required, whose summation gives you $N.
For the sake of this task, please assume 1 is not a prime number.
Example:
Input:
$N = 9
Ouput:
2 as sum of 2 prime numbers i.e. 2 and 7 is same as the input number.
2 + 7 = 9.
For the first challenge I just used goldbach conjecture to figure the min primes for a number … basically 2 for evens and 2 or 3 for odds.
Then I just brute forced it.
Perl 5 solution
#!/usr/bin/perl
# Test: ./ch-1.pl
use Modern::Perl;
use Math::Prime::Util qw /factor is_prime/;
my $N = shift // 9;
say min_primes($N);
# Even primes will always have min 2 primes
# Odds will have min 2 or 3
# AKA goldbach conjecture
sub min_primes {
my $n = shift;
if (is_prime($n)) {
return "$n is already prime";
}
if ($n % 2 == 0) {
my $i = 2;
for (my $j = $n - $i; $j > 2; $j--) {
if (is_prime($i) && is_prime($j)) {
return "$i + $j = $n"
}
$i++;
}
} else {
my $i = 2;
my $possible;
for (my $k = 0; $k < $n - $i; $k++ ) {
next if ( $k != 0
&& ( $k == 1 || !is_prime($k)) );
for (my $j = $n - $i - $k; $j > 2; $j--) {
if ( $k == 0 && is_prime($i)
&& is_prime($j) ) {
return "$i + $j = $n";
}
if ( $k > 0 && is_prime($k)
&& is_prime($i)
&& is_prime($j) ) {
$possible = "$k + $i + $j = $n";
}
$i++;
}
$i = 2;
}
return $possible;
}
}
Output: perl ./ch-1.pl 1212
11 + 1201 = 1212Raku solution
# Test: perl6 ch-1.p6
our %found;
multi MAIN { MAIN(9) };
multi MAIN(Int $N) {
say min-primes($N);
}
# Even primes will always have min 2 primes
# Odds will have min 2 or 3
# AKA goldbach conjecture
sub min-primes(Int $n) {
if ($n.is-prime) {
return "$n is already prime";
}
if ($n % 2 == 0) {
my $i = 2;
loop (my $j = $n - $i; $j > 2; $j--) {
if ($i.is-prime && $j.is-prime) {
return "$i + $j = $n";
}
$i++;
}
} else {
my $i = 2;
my $possible;
loop (my $k = 0; $k < $n - $i; $k++ ) {
next if ( $k != 0 &&
($k == 1 || !$k.is-prime) );
loop (my $j = $n - $i - $k; $j > 2; $j--) {
if ( $k == 0
&& $i.is-prime
&& $j.is-prime ) {
return "$i + $j = $n";
}
if ( $k > 0
&& $k.is-prime
&& $i.is-prime && $j.is-prime ) {
$possible = "$k + $i + $j = $n";
}
$i++;
}
$i = 2;
}
return $possible;
}
}
Output perl6 ch-1.p6 1211
11 + 1201 = 1212TASK #2 › Word Search
Submitted by: Neil Bowers
Reviewed by: Ryan Thompson
Write a script that takes two file names. The first file would contain word search grid as shown below. The second file contains list of words, one word per line. You could even use local dictionary file.
Print out a list of all words seen on the grid, looking both orthogonally and diagonally, backwards as well as forwards.
Search Grid
B I D E M I A T S U C C O R S T
L D E G G I W Q H O D E E H D P
U S E I R U B U T E A S L A G U
N G N I Z I L A I C O S C N U D
T G M I D S T S A R A R E I F G
S R E N M D C H A S I V E E L I
S C S H A E U E B R O A D M T E
H W O V L P E D D L A I U L S S
R Y O N L A S F C S T A O G O T
I G U S S R R U G O V A R Y O C
N R G P A T N A N G I L A M O O
E I H A C E I V I R U S E S E D
S E T S U D T T G A R L I C N H
H V R M X L W I U M S N S O T B
A E A O F I L C H T O D C A E U
Z S C D F E C A A I I R L N R F
A R I I A N Y U T O O O U T P F
R S E C I S N A B O S C N E R A
D R S M P C U U N E L T E S I L
Output
Found 54 words of length 5 or more when checked against the local dictionary. You may or may not get the same result but that is fine.
aimed, align, antes, argos, arose, ashed, blunt, blunts, broad, buries, clove, cloven, constitution, constitutions, croon, depart, departed, enter, filch, garlic, goats, grieve, grieves, hazard, liens, malign, malignant, malls, margo, midst, ought, ovary, parted, patna, pudgiest, quash, quashed, raped, ruses, shrine, shrines, social, socializing, spasm, spasmodic, succor, succors, theorem, theorems, traci, tracie, virus, viruses, wigged
For this challenge, I found a good dictionary file on the web as the mac one only found 39 words.
I then loaded the letters into a matrix and the possible words into a hash and proceeded to run a search pattern running from the top left letter to the bottom right, being careful of boundary conditions. Each of the 8 ortho directions were searched against the hash until a boundary was hit.
Perl 5 solution
#!/usr/bin/perl
# Test: ./ch-2.pl
use Modern::Perl;
use Data::Dumper;
my $matrix = letters_to_matrix(shift);
my $words = dictionary_to_hash(shift);
my $max_height = scalar @$matrix;
my $max_width = scalar @{$matrix->[0]};
my @answers;
# Loop through each letter
# from left to right
for my $i (0 .. $max_height - 1) {
for my $j (0 .. $max_width - 1) {
push @answers,
find_words($matrix, $words, $i,
$j, $max_height, $max_width);
}
}
say "Found " . scalar(@answers) . " words:";
say join ', ', sort @answers;
sub find_words {
my ($matrix, $words, $row, $col, $h, $w) = @_;
my @found;
# Orthogonal directions with 1 on top
# 1t 2tr 3r 4br 5b 6bl 7l 8tl
for my $x (1 .. 8) {
my $i = $row;
my $j = $col;
my $possible_word = '';
while ($i >= 0 && $j >=0 && $i < $h && $j < $w) {
$possible_word .= lc($matrix->[$i][$j]);
push @found, $possible_word
if ($words->{$possible_word});
# Next position calculations
$i-- if ($x == 1 || $x == 2 || $x == 8);
$i++ if ($x == 4 || $x == 5 || $x == 6);
$j-- if ($x == 6 || $x == 7 || $x == 8);
$j++ if ($x == 2 || $x == 3 || $x == 4);
}
}
return @found;
}
# Load the letters into a matrix
sub letters_to_matrix {
my $filename = shift || 'challenge.txt';
my @letter_matrix;
open(my $fh, '<:encoding(UTF-8)', $filename) || die "$@";
while (my $row = <$fh>) {
chomp $row;
my @letters = split (' ', $row);
push @letter_matrix, \@letters;
}
return \@letter_matrix
}
# Load the dictionary into memory
sub dictionary_to_hash {
my $filename = shift || 'words.txt';
my %possible_words;
# Challenge only wants words greater
# than 5 so just keep those
open(my $fh, '<:encoding(UTF-8)', $filename) || die "$@";
while (my $row = <$fh>) {
chomp $row;
$possible_words{lc($row)} = 1
if (length($row) >= 5);
}
return \%possible_words;
}
Output ./ch-2.pl
Found 87 words:
acies, aimed, align, alose, angil, antes, argos, arose, ashed, ation, blunt, blunts, broad, buffa, buries, butea, caeli, clove, cloven, clune, const, constitution, constitutions, cosin, croon, depart, departed, duddie, enter, filch, garlic, goats, grieve, grieves, grith, hazard, hugin, ileac, izing, liens, lunts, malign, malignant, malls, margo, meroe, midst, midsts, neuma, ought, ovary, parte, parted, pasmo, patna, pudgiest, quash, quashed, raias, raped, resor, roser, ruses, shazar, shrine, shrines, sices, social, socializing, soyas, spasm, spasmodic, staun, succor, succors, tallu, talos, talose, theor, theorem, theorems, traci, tracie, virus, viruses, wifie, wiggedRaku solution
# Test: perl6 ch-2.p6
multi MAIN { MAIN("challenge.txt", "words.txt") };
multi MAIN(Str $letter_file, Str $word_file) {
my @matrix = letters-to-matrix($letter_file);
my %words = dictionary-to-hash($word_file);
my @answers;
my $max_height = @matrix.elems;
my $max_width = @matrix.[0].elems;
for (0 .. $max_height - 1) -> $i {
for (0 .. $max_width - 1) -> $j {
my @found =
find-words(@matrix, %words, $i,
$j, $max_height, $max_width);
@answers.push: @found
if @found.elems;
}
}
say "Found " ~ @answers.List.flat.elems ~ " words:";
say @answers.List.flat.sort.join(", ");
}
sub find-words(@matrix, %words, $row, $col, $h, $w) {
my @found;
# Orthogonal directions with 1 on top
# 1t 2tr 3r 4br 5b 6bl 7l 8tl
for (1 .. 8) -> $x {
my $i = $row;
my $j = $col;
my $possible_word = '';
while ($i >= 0 && $j >=0 && $i < $h && $j < $w) {
$possible_word ~= @matrix.[$i][$j].lc;
@found.push($possible_word)
if (%words{$possible_word});
# Next position calculations
$i-- if ($x == 1 || $x == 2 || $x == 8);
$i++ if ($x == 4 || $x == 5 || $x == 6);
$j-- if ($x == 6 || $x == 7 || $x == 8);
$j++ if ($x == 2 || $x == 3 || $x == 4);
}
}
return @found;
}
# Load the letters into a matrix
sub letters-to-matrix(Str $filename) {
my @letter_matrix;
for $filename.IO.lines -> $line {
my @letters = $line.split(" ");
@letter_matrix.push(@letters);
}
return @letter_matrix;
}
# Load the dictionary into memory
sub dictionary-to-hash(Str $filename) {
my %possible_words;
# Challenge only wants words greater
# than 5 so just keep those
for $filename.IO.lines -> $line {
%possible_words{$line.lc} = 1
if ($line.chars >= 5);
}
return %possible_words
}
Output perl6 ch-2.p6
Found 87 words:
acies, aimed, align, alose, angil, antes, argos, arose, ashed, ation, blunt, blunts, broad, buffa, buries, butea, caeli, clove, cloven, clune, const, constitution, constitutions, cosin, croon, depart, departed, duddie, enter, filch, garlic, goats, grieve, grieves, grith, hazard, hugin, ileac, izing, liens, lunts, malign, malignant, malls, margo, meroe, midst, midsts, neuma, ought, ovary, parte, parted, pasmo, patna, pudgiest, quash, quashed, raias, raped, resor, roser, ruses, shazar, shrine, shrines, sices, social, socializing, soyas, spasm, spasmodic, staun, succor, succors, tallu, talos, talose, theor, theorem, theorems, traci, tracie, virus, viruses, wifie, wigged
Perl Weekly Challenge 