challenge-044 andrezgz solution

2 files changed, 116 insertions, 0 deletions

diff --git a/challenge-044/andrezgz/perl/ch-1.pl b/challenge-044/andrezgz/perl/ch-1.pl
new file mode 100644
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+++ b/challenge-044/andrezgz/perl/ch-1.pl
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+#!/usr/bin/perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-044/
+# Task #1
+# Only 100, please.
+# You are given a string "123456789".
+# Write a script that would insert "+" or "-" in between digits
+# so that when you evaluate, the result should be 100.
+
+use strict;
+use warnings;
+
+my @digits = split //, '123456789';
+my $initial = shift @digits;
+
+my %values = ( 0 => '', 1 => '+', 2 => '-' );
+
+# A number in base 3 is used to get a particular combination
+#  for each of the 8 positions between the 9 digits
+# The combination is left padded with zeros to get exactly 8 digits for lower numbers
+#
+# The 8 digits from a combination define an equation
+#  translating each one to its value: +, - or '' (empty)
+#  and concatenating it with the corresponding digit from the given number
+
+foreach my $n (0 .. (3**8)-1) {
+    my $equation = $initial;
+    my @combination = split //, sprintf "%08d", to_base3($n);
+    $equation .= $values{ $combination[$_] } . $digits[$_] for (0 .. @digits - 1);
+    print "$equation\n" if (eval $equation == 100);
+}
+
+
+sub to_base3 {
+    my ($n) = @_;
+    return 0 if ($n == 0);
+
+    my $result;
+    while ($n > 0) {
+        $result .= $n % 3;
+        $n = int($n / 3);
+    }
+    # force scalar context to assure returning a reversed string
+    return scalar reverse $result;
+}
+
+__END__
+
+./ch-1.pl
+123+45-67+8-9
+123+4-5+67-89
+123-45-67+89
+123-4-5-6-7+8-9
+12+3+4+5-6-7+89
+12+3-4+5+67+8+9
+12-3-4+5-6+7+89
+1+23-4+56+7+8+9
+1+23-4+5+6+78-9
+1+2+34-5+67-8+9
+1+2+3-4+5+6+78+9
diff --git a/challenge-044/andrezgz/perl/ch-2.pl b/challenge-044/andrezgz/perl/ch-2.pl
new file mode 100644
index 0000000000..2a8e999576
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+++ b/challenge-044/andrezgz/perl/ch-2.pl
@@ -0,0 +1,56 @@
+#!/usr/bin/perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-044/
+# Task #2
+# Make it $200
+# You have only $1 left at the start of the week.
+# You have been given an opportunity to make it $200.
+# The rule is simple with every move you can either double what you have or add another $1.
+# Write a script to help you get $200 with the smallest number of moves.
+
+use strict;
+use warnings;
+
+# an upper bound of moves to check
+use constant MOVES_LIMIT => 10;
+
+my @solution;
+
+# A binary number is used to get a particular combination
+#  for each of the moves to check
+#
+# The combination defines a serie of operations (add 1 or multiply by 2)
+# Each one of them updates the value for the next operation.
+
+foreach my $n ( 0 .. (2 ** MOVES_LIMIT)-1 ) {
+    my @ops = map { $_ ? '+ 1' : '* 2'} split //, sprintf("%b", $n);
+
+    my $value = 1;
+    $value = eval($value . $_) for (@ops);
+
+    if ($value == 200) {
+        @solution = @ops;
+        last;
+    }
+}
+
+# beautified solution printing
+my $value = 1;
+print $value . $/;
+foreach (@solution) {
+    $value = eval($value . $_);
+    print $_.' = '. $value . $/;
+}
+
+__END__
+./ch-2.pl
+1
++ 1 = 2
++ 1 = 3
+* 2 = 6
+* 2 = 12
+* 2 = 24
++ 1 = 25
+* 2 = 50
+* 2 = 100
+* 2 = 200