Merge pull request #9575 from mattneleigh/pwc256

Pwc256

2 files changed, 153 insertions, 0 deletions

diff --git a/challenge-256/mattneleigh/perl/ch-1.pl b/challenge-256/mattneleigh/perl/ch-1.pl
new file mode 100755
index 0000000000..eb6b3a9628
--- /dev/null
+++ b/challenge-256/mattneleigh/perl/ch-1.pl
@@ -0,0 +1,76 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @word_lists = (
+    [ "ab", "de", "ed", "bc" ],
+    [ "aa", "ba", "cd", "ed" ],
+    [ "uv", "qp", "st", "vu", "mn", "pq" ]
+);
+
+print("\n");
+foreach my $word_list (@word_lists){
+    printf(
+        "Input: \@words = (%s)\nOutput:  %d\n\n",
+        join(
+            ", ",
+            map(
+                "\"" . $_ . "\"",
+                @{$word_list}
+            )
+        ),
+        count_reversed_pairs(@{$word_list})
+    );
+}
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Given a list of distinct words, count the number of reversed pairs in the
+# list- that is to say, the pairs of strings in which one string is the reverse
+# of the other
+# Takes one argument:
+# * The list of words to examine (e.g. ( "uv", "qp", "st", "vu", "mn", "pq" ) )
+# Returns:
+# * The count of reversed pairs (e.g. 2 )
+################################################################################
+sub count_reversed_pairs{
+
+    my $pairs = 0;
+    my @reversed;
+    my $j;
+
+    # Store reversed copies of every word that $j
+    # will refer to later in the nested loop below
+    for $j (1 .. $#ARG){
+        $reversed[$j] = join("", reverse(split("", $ARG[$j])));
+    }
+
+    # Compare every original string with every
+    # reversed equivalent
+    for my $i (0 .. $#ARG - 1){
+        for $j ($i + 1 .. $#ARG){
+            # Increment the counter if the string at $i
+            # matches the reversed string at $j
+            $pairs++
+                if($ARG[$i] eq $reversed[$j]);
+        }
+    }
+
+    return($pairs);
+
+}
+
+
+
diff --git a/challenge-256/mattneleigh/perl/ch-2.pl b/challenge-256/mattneleigh/perl/ch-2.pl
new file mode 100755
index 0000000000..8e275c5719
--- /dev/null
+++ b/challenge-256/mattneleigh/perl/ch-2.pl
@@ -0,0 +1,77 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @string_lists = (
+    [ "abcd", "1234" ],
+    [ "abc", "12345" ],
+    [ "abcde", "123" ]
+);
+
+print("\n");
+foreach my $string_list (@string_lists){
+    printf(
+        "Input: \$str1 = \"%s\", \$str2 = \"%s\"\nOutput: \"%s\"\n\n",
+        $string_list->[0],
+        $string_list->[1],
+        merge_from_alternate_strings(@{$string_list})
+    );
+}
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Given two strings, merge them by combining one character from each, in
+# alternating order, starting with the first string; if one string is longer
+# than the other, remaining characters from it will be appended at the end
+# Takes two arguments:
+# * The first string to concatenate (e.g. "abc")
+# * The second string to concatenate (e.g. "12345")
+# Returns:
+# * A string merged as defined above (e.g. "a1b2c345")
+################################################################################
+sub merge_from_alternate_strings{
+
+    my $length1 = length($ARG[0]);
+    my $length2 = length($ARG[1]);
+    my $minimum_common_length = $length1 < $length2 ?
+        $length1
+        :
+        $length2;
+    my $merged = "";
+
+    # Over the length the strings have in common,
+    # concatenate a pair of characters from each
+    for my $pos (0 .. $minimum_common_length - 1){
+        $merged .=
+            substr($ARG[0], $pos, 1)
+            .
+            substr($ARG[1], $pos, 1);
+    }
+
+    # At least one string has been used up; if one
+    # is longer than the minimum common length,
+    # concatenate the remaining characters from it
+    if($length1 > $minimum_common_length){
+        $merged .= substr($ARG[0], $minimum_common_length);
+    } elsif($length2 > $minimum_common_length){
+        $merged .= substr($ARG[1], $minimum_common_length);
+    }
+
+    return($merged);
+
+}
+
+
+