Merge pull request #10690 from mattneleigh/pwc283

new file:   challenge-283/mattneleigh/perl/ch-1.pl

2 files changed, 157 insertions, 0 deletions

diff --git a/challenge-283/mattneleigh/perl/ch-1.pl b/challenge-283/mattneleigh/perl/ch-1.pl
new file mode 100755
index 0000000000..4ee777fc16
--- /dev/null
+++ b/challenge-283/mattneleigh/perl/ch-1.pl
@@ -0,0 +1,75 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @integer_lists = (
+    [ 3, 3, 1 ],
+    [ 3, 2, 4, 2, 4 ],
+    [ 1 ],
+    [ 4, 3, 1, 1, 1, 4 ]
+);
+
+print("\n");
+foreach my $integer_list (@integer_lists){
+    my $rval = find_solitary_element(@{$integer_list});
+
+    printf(
+        "Input: \@ints = (%s)\nOutput: %d\n\n",
+        join(", ", @{$integer_list}),
+        defined($rval) ?
+            $rval
+            :
+            0
+    );
+}
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Given an array of integers, find one that appears only once
+# Takes one argument:
+# * An array of integers to examine (e.g. ( 3, 3, 1 ) )
+# Returns on success:
+# * An element that appears only once; if more than one element qualifies, the
+#   first is returned (e.g. 1 )
+# Returns on error:
+# * undef if no element was found only once
+################################################################################
+sub find_solitary_element{
+
+    my %frequency_table;
+    my $int;
+
+    # Build a frequency table, counting instances
+    # of each element
+    foreach $int (@ARG){
+        $frequency_table{$int}++;
+    }
+
+    # Examine the frequency of each element
+    foreach $int (@ARG){
+        # Found something that appeared once- return
+        # it
+        return($int)
+            if($frequency_table{$int} == 1);
+    }
+
+    # Got here?  Must not have found anything that
+    # appeared only once
+    return(undef);
+
+}
+
+
+
diff --git a/challenge-283/mattneleigh/perl/ch-2.pl b/challenge-283/mattneleigh/perl/ch-2.pl
new file mode 100755
index 0000000000..66e2e9018a
--- /dev/null
+++ b/challenge-283/mattneleigh/perl/ch-2.pl
@@ -0,0 +1,82 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @integer_lists = (
+    [ 1, 2, 1, 0 ],
+    [ 0, 3, 0 ]
+);
+
+print("\n");
+foreach my $integer_list (@integer_lists){
+    printf(
+        "Input: \@ints = (%s)\nOuput: %s\n\n",
+        join(", ", @{$integer_list}),
+        verify_index_quantity_correlation(@{$integer_list}) ?
+            "true"
+            :
+            "false"
+    );
+}
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Given an array of positive integers, determine wherther the value of each
+# index $i appears within the array a number of times equal to the value stored
+# in the array at that index
+# Takes one argument:
+# * The list of digits eo examine (e.g. (1, 2, 1, 0) )
+# Returns:
+# * 0 if any digit did not appear in the expected quantity
+# * 1 if all digits appeared in the expected quantity, as would be the case for
+#   the example above, for 0 appears 1 time, 1 appears 2 times, 2 appears 1
+#   time, and 3 appears 0 times.
+################################################################################
+sub verify_index_quantity_correlation{
+
+    my %frequency_table;
+
+    # Build a frequency table, counting instances
+    # of each digit
+    foreach my $digit (@ARG){
+        $frequency_table{$digit}++
+    }
+
+    # Loop over each index in the given array
+    foreach my $i (0 .. $#ARG){
+        # Return zero if the frequency count for this
+        # index does not match the array value at
+        # this index
+        return(0)
+            unless(
+                # Digits we never saw get an effective count
+                # of 0
+                defined($frequency_table{$i}) ?
+                    $frequency_table{$i}
+                    :
+                    0
+                ==
+                $ARG[$i]
+            );
+    }
+
+    # Got here- every digit occurred in the
+    # correct quantity
+    return(1);
+
+}
+
+
+