first few days

1/1.pl

@@ -0,0 +1,13 @@
+#!/usr/bin/perl
+
+use strict;
+
+my $start = 0;
+
+while (<>) {
+chomp;
+
+$start += $_;
+
+}
+print $start . "\n";

1/2.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+
+use strict;
+
+my $freq = 0;
+my %seen;
+
+chomp (my @data = <STDIN>);
+
+while () {
+	foreach (@data) {
+		$freq += $_;
+		if ($seen{$freq} == 1) {
+			print $freq . "\n";
+			exit;
+		}
+		$seen{$freq}++;
+	}
+}

2/1.pl

@@ -0,0 +1,35 @@
+#!/usr/bin/perl
+
+use strict;
+
+chomp (my @data = <STDIN>);
+
+my ($ck2, $ck3);
+foreach my $w (@data) {
+	my ($r2, $r3) = checksum($w);
+	#print "$r2, $r3\n";
+	$ck2 += $r2;
+	$ck3 += $r3;
+}
+print $ck2 * $ck3 . "\n";
+
+
+sub checksum {
+	my $word = shift;
+	
+	my %seen;
+	foreach my $letter (split //, $word) {
+		$seen{$letter}++
+	}
+
+	my $twos = 0;
+	my $threes = 0;
+	foreach my $k (keys %seen) {
+		# print "$k $seen{$k}\n";
+		$twos=1 if ($seen{$k} == 2);
+		$threes=1 if ($seen{$k} == 3);
+	}
+
+	return ($twos, $threes);
+
+}

2/2.pl

@@ -0,0 +1,40 @@
+#!/usr/bin/perl
+
+use strict;
+
+chomp (my @data = <STDIN>);
+
+foreach my $w (@data) {
+	print checksum($w, @data);
+}
+
+
+
+sub checksum ($@) {
+	my $word = shift;
+	my @list = @_;
+
+	my @word = split //, $word;
+	
+	foreach my $w (@list) {
+		
+		my @w = split //, $w;
+		# word lengths are all equal.
+
+		my $diff = 0;
+		my $common;
+		for (my $i = 0; $i <= $#word; $i++) {
+			if ($word[$i] ne $w[$i]) {
+				$diff++
+			} else {
+				$common .= $w[$i];
+			}
+		}
+		if ($diff == 1) {
+			print "$word, $w, $diff, $common\n";
+			exit;
+		}
+
+	}
+
+}

2/sample.txt

@@ -0,0 +1,7 @@
+abcdef
+bababc
+abbcde
+abcccd
+aabcdd
+abcdee
+ababab

2/sample2.txt

@@ -0,0 +1,7 @@
+abcde
+fghij
+klmno
+pqrst
+fguij
+axcye
+wvxyz

3/1.pl

@@ -0,0 +1,39 @@
+#!/usr/bin/perl
+
+use strict;
+
+chomp (my @data = <STDIN>);
+my %seen;
+
+foreach my $line (@data) {
+    # #1 @ 1,3: 4x4
+    #print $line . "\n";
+    my ($id, $sx, $sy, $w, $h) = ($line =~ m/#(\d+) @ (\d+),(\d+): (\d+)x(\d+)/);
+
+    foreach my $r (expand_area($sx, $sy, $w, $h)) {
+        #print "A: $r\n";
+        $seen{$r}++
+    }
+
+}
+
+my $count = 0;
+foreach my $k (keys %seen) {
+    #print "F: $k $seen{$k}\n";
+    if ($seen{$k} > 1) {
+        $count++
+    }
+}
+print $count . "\n";
+
+sub expand_area ($$$$) {
+    my @r;
+    my ($sx, $sy, $w, $h) = @_;
+    for (my $i = 0; $i < $w; $i++) {
+        for (my $j = 0; $j < $h; $j++) {
+            my $s = (($sx+$i) . "," . ($sy+$j));
+            push @r, $s;
+        }
+    }
+    return @r;
+}

3/2.pl

@@ -0,0 +1,56 @@
+#!/usr/bin/perl
+
+use strict;
+
+chomp (my @data = <STDIN>);
+my %seen;
+my %area;
+my %overlapped;
+
+foreach my $line (@data) {
+    # #1 @ 1,3: 4x4
+    #print $line . "\n";
+    my ($id, $sx, $sy, $w, $h) = ($line =~ m/#(\d+) @ (\d+),(\d+): (\d+)x(\d+)/);
+    $overlapped{$id} = 1;
+
+    foreach my $r (expand_area($sx, $sy, $w, $h)) {
+        #print "A: $r\n";
+        $seen{$r}++;
+        $area{$r}->{$id}++;
+    }
+
+}
+
+my $count = 0;
+foreach my $k (keys %seen) {
+    #print "F: $k $seen{$k}\n";
+    if ($seen{$k} > 1) {
+        $count++
+    }
+}
+print $count . "\n";
+
+foreach my $k (keys %area) {
+    my $h = $area{$k};
+    my @a = keys %$h;
+    if ($#a >= 1) {
+        foreach my $o (keys %$h) {
+            delete $overlapped{$o} 
+        }
+    }
+}
+use Data::Dumper;
+print Dumper \%overlapped;
+
+
+sub expand_area ($$$$) {
+    my @r;
+    my ($sx, $sy, $w, $h) = @_;
+    for (my $i = 0; $i < $w; $i++) {
+        for (my $j = 0; $j < $h; $j++) {
+            my $s = (($sx+$i) . "," . ($sy+$j));
+            push @r, $s;
+        }
+    }
+    return @r;
+}

3/sample.txt

@@ -0,0 +1,3 @@
+#1 @ 1,3: 4x4
+#2 @ 3,1: 4x4
+#3 @ 5,5: 2x2

4/1.pl

@@ -0,0 +1,47 @@
+#!/usr/bin/perl
+
+use strict;
+use v5.10;
+use Data::Dumper;
+
+chomp (my @data = <STDIN>);
+@data = sort @data;
+
+my %sleeps;
+my %most;
+my $currentguard = -1;
+my $sleeptime = -1;
+
+foreach my $line (@data) {
+    say $line;
+    if ( my ($date, $hour, $min, $guard) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] Guard #(\d+) begins shift/) ) {
+            $currentguard = $guard;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] falls asleep/) ) {
+            $sleeptime = $min;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] wakes up/) ) {
+            foreach my $mt ($sleeptime .. $min-1) {
+                $sleeps{$currentguard}->{$mt}++;
+                $most{$currentguard}++;
+            }
+        }
+    else {
+        say "no match"
+    }
+}
+
+my @most = sort { $most{$b} <=> $most{$a} } keys %most; 
+say $most[0] . " most, with " . $most{$most[0]};
+
+my $result = $sleeps{$most[0]};
+my @best = sort { $$result{$b} <=> $$result{$a} } keys %$result; 
+
+say $best[0] . " best minute";
+say ($best[0] * $most[0]);

4/2.pl

@@ -0,0 +1,60 @@
+#!/usr/bin/perl
+
+use strict;
+use v5.10;
+use Data::Dumper;
+
+chomp (my @data = <STDIN>);
+@data = sort @data;
+
+my %sleeps;
+my %most;
+my $currentguard = -1;
+my $sleeptime = -1;
+
+foreach my $line (@data) {
+    say $line;
+    if ( my ($date, $hour, $min, $guard) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] Guard #(\d+) begins shift/) ) {
+            $currentguard = $guard;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] falls asleep/) ) {
+            $sleeptime = $min;
+        }
+    elsif ( my ($date, $hour, $min) = 
+        ($line =~ 
+        m/\[(\d{4}-\d{2}-\d{2}) (\d{2}):(\d{2})\] wakes up/) ) {
+            foreach my $mt ($sleeptime .. $min-1) {
+                $sleeps{$currentguard}->{$mt}++;
+                $most{$currentguard}++;
+            }
+        }
+    else {
+        say "no match"
+    }
+}
+
+my @most = sort { $most{$b} <=> $most{$a} } keys %most; 
+say $most[0] . " most, with " . $most{$most[0]};
+
+my $result = $sleeps{$most[0]};
+my @best = sort { $$result{$b} <=> $$result{$a} } keys %$result; 
+
+say $best[0] . " best minute";
+say ($best[0] * $most[0]);
+
+my ($p2guard, $p2min, $p2count);
+foreach my $guard (keys %sleeps) {
+    my $result = $sleeps{$guard};
+    my @best = sort { $$result{$b} <=> $$result{$a} } keys %$result; 
+    say $guard .  " with min " . $best[0] . ": " . $$result{$best[0]};
+    if ($$result{$best[0]} > $p2count) {
+        $p2count = $$result{$best[0]};
+        $p2guard = $guard;
+        $p2min = $best[0];
+    }
+}
+say "$p2guard, $p2count, $p2min: " . $p2guard * $p2min;

4/sample.txt

@@ -0,0 +1,17 @@
+[1518-11-01 00:00] Guard #10 begins shift
+[1518-11-01 00:05] falls asleep
+[1518-11-01 00:25] wakes up
+[1518-11-01 00:30] falls asleep
+[1518-11-01 00:55] wakes up
+[1518-11-01 23:58] Guard #99 begins shift
+[1518-11-02 00:40] falls asleep
+[1518-11-02 00:50] wakes up
+[1518-11-03 00:05] Guard #10 begins shift
+[1518-11-03 00:24] falls asleep
+[1518-11-03 00:29] wakes up
+[1518-11-04 00:02] Guard #99 begins shift
+[1518-11-04 00:36] falls asleep
+[1518-11-04 00:46] wakes up
+[1518-11-05 00:03] Guard #99 begins shift
+[1518-11-05 00:45] falls asleep
+[1518-11-05 00:55] wakes up