Merge pull request #944 from jaldhar/challenge-034

Challenge 34 by Jaldhar H. Vyas: the missing challenge.

1 files changed, 55 insertions, 0 deletions

diff --git a/challenge-034/jaldhar-h-vyas/perl5/ch-1.pl b/challenge-034/jaldhar-h-vyas/perl5/ch-1.pl
new file mode 100755
index 0000000000..b245e5c543
--- /dev/null
+++ b/challenge-034/jaldhar-h-vyas/perl5/ch-1.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use 5.010;
+
+sub pick {
+    my @range = @{$_[0]};
+    my $quantity = $_[1];
+
+    if ($quantity < 1 || $quantity > scalar @range) {
+        die "out of range\n";
+    }
+
+    my @picked;
+
+    for my $i (0 .. $quantity) {
+        my $try = q{ };
+        while ($try eq q{ }) {
+            $try = $range[int(rand(scalar @range))];
+        }
+        @range = map { $_ eq $try ? q{ } : $_; } @range;
+        push @picked, $try;
+    }
+
+    return wantarray ? @picked : $picked[0];
+}
+
+sub binarySearch {
+    my @haystack = @{$_[0]};
+    my $needle = $_[1];
+
+    if (@haystack && scalar @haystack) {
+        my $mid = int (scalar @haystack / 2); 
+
+        if ($needle eq $haystack[$mid]) { 
+            return 1;
+        }
+
+        if ($needle gt $haystack[$mid]) {
+            return binarySearch([@haystack[$mid + 1 .. scalar @haystack - 1]],
+                $needle);
+        } 
+
+        return binarySearch([@haystack[0 .. $mid - 1]], $needle);
+    }
+
+    return undef;
+}
+
+my @letters = ('a' .. 'z');
+my @haystack = pick([@letters], scalar @letters / 2);
+my $needle = pick([@letters], 1);
+say "is $needle in ", (join q{}, @haystack), '?';
+say binarySearch([sort @haystack], $needle) ? 'Yes.' : 'No.';
+