Merge pull request #2445 from ccntrq/challenge-080

Challenge 080

4 files changed, 93 insertions, 3 deletions

diff --git a/challenge-080/alexander-pankoff/README b/challenge-080/alexander-pankoff/README
index f1aacf3dba..a74e2fd1ec 100644
--- a/challenge-080/alexander-pankoff/README
+++ b/challenge-080/alexander-pankoff/README
@@ -1,6 +1,10 @@
 Solution by Alexander Pankoff
 
-# ch-1
+# Run the Haskell solution
 
-Aproach taken from:
-https://www.geeksforgeeks.org/count-total-set-bits-in-all-numbers-from-1-to-n/
+With a `ghc` installation you can run the haskell solution with `runghc`
+
+```
+$ runghc haskell/ch-1.hs 1 2 3 -1 4
+5
+```
diff --git a/challenge-080/alexander-pankoff/haskell/ch-1.hs b/challenge-080/alexander-pankoff/haskell/ch-1.hs
new file mode 100644
index 0000000000..d27f32fdd7
--- /dev/null
+++ b/challenge-080/alexander-pankoff/haskell/ch-1.hs
@@ -0,0 +1,27 @@
+import System.Environment (getArgs)
+import Data.List (find)
+import qualified Data.Set as Set
+
+type IntegerSet = Set.Set Integer
+
+main :: IO ()
+main = do
+  inputSet <- Set.fromList <$> (readInteger <<$>> getArgs)
+  let maybeMissing = smallestMissingPositiveNumber inputSet
+  maybe
+    (fail "no smallest missing number found.")
+    print
+    maybeMissing
+  where
+   readInteger :: String -> Integer
+   readInteger = read
+
+smallestMissingPositiveNumber :: IntegerSet -> Maybe Integer
+smallestMissingPositiveNumber set = find (not . inSet) [1..]
+ where
+  inSet = (`Set.member` set)
+
+infixl 4 <<$>>
+
+(<<$>>) :: (Functor f, Functor g) => (a -> b) -> f (g a) -> f (g b)
+(<<$>>) = fmap . fmap
diff --git a/challenge-080/alexander-pankoff/perl/ch-1.pl b/challenge-080/alexander-pankoff/perl/ch-1.pl
new file mode 100644
index 0000000000..d6ef9089ee
--- /dev/null
+++ b/challenge-080/alexander-pankoff/perl/ch-1.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/env perl
+use v5.20;
+use utf8;
+use strict;
+use warnings;
+use autodie;
+use feature qw(say signatures);
+no warnings 'experimental::signatures';
+
+use List::Util qw(first);
+
+say smallest_positive_number_missing(@ARGV);
+
+sub smallest_positive_number_missing( @xs) {
+    my %lookup = map { $_ => 1 } @xs;
+    return first { !$lookup{$_} } 1 .. ( @xs + 1 );
+}
+
diff --git a/challenge-080/alexander-pankoff/perl/ch-2.pl b/challenge-080/alexander-pankoff/perl/ch-2.pl
new file mode 100644
index 0000000000..b30e3c2cf0
--- /dev/null
+++ b/challenge-080/alexander-pankoff/perl/ch-2.pl
@@ -0,0 +1,41 @@
+#!/usr/bin/env perl
+use v5.20;
+use utf8;
+use strict;
+use warnings;
+use autodie;
+use feature qw(say signatures);
+no warnings 'experimental::signatures';
+
+use List::Util qw(max sum0);
+
+say count_candies(@ARGV);
+
+sub count_candies(@candidates) {
+    my $descending;
+    my @candies;
+    for my $i ( 0 .. $#candidates ) {
+
+        if ( $i > 0 && $candidates[ $i - 1 ] < $candidates[$i] ) {
+            $candies[$i] = $candies[ $i - 1 ] + 1;
+        }
+        else {
+            $candies[$i] = 1;
+        }
+
+        if ( $i < $#candidates && $candidates[$i] > $candidates[ $i + 1 ] ) {
+            $descending++;
+        }
+        else {
+            while ($descending) {
+                my $candies = $descending + 1;
+                if ( $candies[ $i - $descending ] < $candies ) {
+                    $candies[ $i - $descending ] = $candies;
+                }
+                $descending--;
+            }
+        }
+    }
+    return sum0(@candies);
+}
+