Create ch-1.pl

1 files changed, 77 insertions, 0 deletions

diff --git a/challenge-050/user-person/perl/ch-1.pl b/challenge-050/user-person/perl/ch-1.pl
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+#!/usr/bin/env perl
+
+###########################################################################
+# script name: ch-1.pl                                                    #
+#                                                                         #
+# https://github.com/user-person                                          #
+#                                                                         #
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-050/         #
+#                                                                         #
+# Merge Intervals                                                         #
+# Write a script to merge the given intervals where ever possible.        #
+#                                                                         #
+# [2,7], [3,9], [10,12], [15,19], [18,22]                                 #
+#                                                                         #
+# The script should merge [2, 7] and [3, 9] together to return [2, 9].    #
+#                                                                         #
+# Similarly it should also merge [15, 19] and [18, 22] together to        #
+# return [15, 22].                                                        #
+#                                                                         #
+# The final result should be something like below:                        #
+#                                                                         #
+# [2, 9], [10, 12], [15, 22]                                              #
+#                                                                         #
+###########################################################################
+
+use strict;
+use warnings;
+use List::MoreUtils qw( minmax );
+
+my $input = "[2,7], [3,9], [10,12], [15,19], [18,22]";
+
+$input = "@ARGV" if @ARGV;
+
+$input =~ s{[][, ]+}{ }g;
+$input =~ s{\A\s+|\s+\Z}{};
+
+my @sets = split m{ }, $input;
+
+sub printSets {
+    for (my $i=0; $i < $#_; $i += 2) {
+        print "[$_[$i], $_[$i+1]]";
+        print ", " if $i+1 < $#_;
+    }
+    print "\n";
+}
+
+sub mergeUnits {
+    my @indicies = @_;
+    my ($min, $max) = minmax ( $sets[$indicies[0]], $sets[$indicies[1]], $sets[$indicies[2]], $sets[$indicies[3]] );
+    push @sets, $min;
+    push @sets, $max;
+
+    foreach ( sort { $b <=> $a } @indicies ) {
+        splice @sets, $_, 1;
+    }
+}
+
+print "UNMERGED:\n";
+printSets @sets;
+
+OUTER:
+for (my $j=0; $j < $#sets; $j += 2) {
+    for ( my $k=$j+2; $k < $#sets; $k += 2) {
+
+        if ( $sets[$k] >= $sets[$j] and $sets[$k] <= $sets[$j+1]
+                     or $sets[$k+1] >= $sets[$j] and $sets[$k+1] <= $sets[$j+1] ) {
+
+            mergeUnits $j, $j+1, $k, $k+1;
+            $j = -2;            # This resets OUTER loop to 0 after its double increment
+            next OUTER;
+        }
+    }
+}
+
+@sets = sort { $a <=> $b } @sets;
+print "\nMERGED:\n";
+printSets @sets;