Challenge 79

3 files changed, 100 insertions, 0 deletions

diff --git a/challenge-079/dave-jacoby/perl/= b/challenge-079/dave-jacoby/perl/=
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/challenge-079/dave-jacoby/perl/=
diff --git a/challenge-079/dave-jacoby/perl/ch-1.pl b/challenge-079/dave-jacoby/perl/ch-1.pl
new file mode 100755
index 0000000000..b1e4bff87e
--- /dev/null
+++ b/challenge-079/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,30 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say signatures state };
+no warnings qw{ experimental };
+
+use Carp;
+use List::Util qw{ sum };
+use Getopt::Long;
+
+my $n = 4;
+GetOptions( 'n=i' => \$n, );
+croak 'Non-positive number' if $n < 0;
+
+my $total = count_set_bits($n);
+say $total;
+
+sub count_set_bits( $n ) {
+    my $total = 0;
+    my $t     = 0;
+    for my $i ( 0 .. $n ) {
+        my $b = sprintf '%b', $i;
+        my $c = sum split m{|}, $b;
+        $total += $c;
+        $t = $total % 1000000007;
+    }
+
+    return $t;
+}
diff --git a/challenge-079/dave-jacoby/perl/ch-2.pl b/challenge-079/dave-jacoby/perl/ch-2.pl
new file mode 100755
index 0000000000..b2b8265e48
--- /dev/null
+++ b/challenge-079/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,70 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say signatures state };
+no warnings qw{ experimental };
+
+use Getopt::Long;
+use List::Util qw{ max sum0 };
+
+my @n = grep { $_ >= 1 } @ARGV;
+@n = ( 2, 1, 4, 1, 2, 5 ) unless scalar @n;
+
+# make_histogram(@n);
+my $trapped = trap_rain_water(@n);
+
+my $units = $trapped == 1 ? 'unit' : 'units';
+say qq{$trapped $units trapped};
+
+sub make_histogram ( @n ) {
+    my $max = max @n;
+    say '';
+    for my $i ( reverse 1 .. $max ) {
+        my @h = map { $i <= $_ ? '#' : ' ' } @n;
+        say join ' ', $i, @h;
+    }
+    say join '-', ' ', map { '-' } @n;
+    say join ' ', ' ', @n;
+    say '';
+}
+
+sub trap_rain_water ( @n ) {
+    my $max = max @n;
+    my $s   = scalar @n;
+    my $c   = 0;
+
+    my @hist;
+
+    for my $i ( reverse 1 .. $max ) {
+        my $z = sum0 map { $i <= $_ ? 1 : 0 } @n;
+        my @h;
+        my $hh = [];
+        push $hh->@*, $i, '';
+
+        for my $j ( 0 .. $s - 1 ) {
+            my $e = $n[$j];              # equals
+            my $p = $e >= $i ? 1 : 0;    # is peak
+
+            my @lt = @n[ 0 .. $j - 1 ];
+            my @gt = @n[ $j + 1 .. $s - 1 ];
+            my $lt = scalar grep { $_ >= $i } @lt;          # is peak to left
+            my $gt = scalar grep { $_ >= $i } @gt;          # is peak to right
+            my $t  = $p != 1 && $lt > 0 && $gt > 0 ? 1 : 0; # has trapped
+            $c += $t;
+
+            push @h, $e >= $i ? '#' : $t;
+            my $v = ' ';
+            $v = '#' if $p;
+            $v = '.' if $t;
+            push $hh->@*, $v;
+        }
+
+        push @hist, $hh;
+    }
+
+    say join "\n", map { join ' ', $_->@* } @hist, [], [ ' ', '', @n ];
+    say '';
+
+    return $c;
+}