Merge pull request #5315 from pjcs00/branch-for-challenge-141

Committed solutions to challenge 141

3 files changed, 113 insertions, 0 deletions

diff --git a/challenge-141/peter-campbell-smith/blog.txt b/challenge-141/peter-campbell-smith/blog.txt
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+https://pjcs-pwc.blogspot.com/2021/12/perl-weekly-challenge-141-task-1-reads.html
diff --git a/challenge-141/peter-campbell-smith/ch-1.pl b/challenge-141/peter-campbell-smith/ch-1.pl
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+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2021-11-29
+# PWC 141 task 1
+
+use v5.20;
+use warnings;
+use strict;
+
+# Write a script to find lowest 10 positive integers having exactly 8 divisors.
+# Example: 24 is the first such number having exactly 8 divisors:
+# 1, 2, 3, 4, 6, 8, 12 and 24.
+
+# Some thoughts on this challenge: https://pjcs-pwc.blogspot.com/2021/12/perl-weekly-challenge-141-task-1-reads.html
+
+my ($test, @tests, $try, $divisor, $dividend, $key, $count, $string, $num, $how_many, $num_divisors,
+	$max_try, $z);
+
+# inputs - pairs of number of results to show and number of divisors required
+@tests = ([10, 8]);
+$max_try = 10000;
+
+# loop over tests
+for $test (@tests) {
+	($how_many, $num_divisors) = @$test;
+	say qq[\nSmallest $how_many numbers (up to $max_try) having $num_divisors divisors:];
+
+	# initialise
+	$num_divisors --;
+	$how_many -= 1;
+	$num = 0;
+
+	# loop over integers
+	TRY: for $try (2..$max_try) {
+		$count = 0;     # number of divisors found
+		$string = '';   # list of divisors
+
+		# loop over potential divisors
+		for $divisor (1..int($try/2)) {
+			$dividend = $try/$divisor;
+
+			# if it is a divisor
+			if ($dividend eq int($dividend)) {
+				$count ++;
+				$string .= qq[$divisor, ];
+				next TRY if $count > $num_divisors;   # give up if there are too many
+			}
+		}
+
+		# if there were exactly the number of divisors requested we have an answer
+	    if ($count == $num_divisors) {
+			say qq[$try has divisors $string$try];    # add the number itself to the list
+			last if $num ++ >= $how_many;               # stop if we have enough answers
+		}
+	}
+}
diff --git a/challenge-141/peter-campbell-smith/ch-2.pl b/challenge-141/peter-campbell-smith/ch-2.pl
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+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2021-12-01
+# PWC 141 task 2
+
+use v5.20;
+use warnings;
+use strict;
+
+# You are given positive integers, $m and $n.
+# Write a script to find total count of integers created using the digits
+# of $m which is also divisible by $n.
+
+my (@tests, $test, $m, $n, $num_digits, @digits, $i, $iter, $c,
+	$extract, $all, $good, $num_good);
+
+use Algorithm::Combinatorics qw(combinations);
+
+# pairs of $m and $n
+@tests = ([1234, 2], [768, 4], [1234567, 31]);
+
+# loop over pairs
+for $test (@tests) {
+	$all = $good = '';
+	$num_good = 0;
+	($m, $n) = @$test;
+
+	# split $m into an array of digits
+	$num_digits = length($m);
+	@digits = split(//, $m);
+
+	# need all the combinations of 1, 2 ... (length - 1) digits
+	for $i (1..$num_digits - 1) {
+        $iter = combinations(\@digits, $i);
+
+		# loop over combinations
+		while ($c = $iter->next) {
+
+			# join digits of combination together
+			$extract = join('', @$c);
+
+			# create string of $all combs and $good combs divisible by $n
+			$all .= qq[$extract, ];
+            if ($extract % $n == 0) {
+				$good .= qq[$extract, ];
+				$num_good ++;
+			}
+		}
+	}
+
+	# trim trailing commas and show answer
+	$all =~ s|..$||;
+	$good =~ s|..$||;
+	say qq[Possible integers created using the digits of $m are:\n$all];
+	say qq[There are $num_good integers divisible by $n which are:\n$good\n];
+}