From dd729f69ee696341e8f2298c5cc7b703cdc8c03c Mon Sep 17 00:00:00 2001
From: Julich Mera <mera7617@gmail.com>
Date: Fri, 14 Nov 2014 16:06:11 -0500
Subject: [PATCH] Add ruby solution for array pair sum, made minor change to
 balanced brackets problem.

---
 solutions/ruby/array_pair_sum.rb    | 15 +++++++++++++++
 solutions/ruby/balanced_brackets.rb |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 solutions/ruby/array_pair_sum.rb

diff --git a/solutions/ruby/array_pair_sum.rb b/solutions/ruby/array_pair_sum.rb
new file mode 100644
index 0000000..f0c70e9
--- /dev/null
+++ b/solutions/ruby/array_pair_sum.rb
@@ -0,0 +1,15 @@
+def array_pair_sum(sum, arr)
+  result = []
+  seen = Hash.new(false)
+  while elem = arr.shift
+    target = sum - elem
+    (seen[elem] || seen[target]) ? next : (seen[elem] = true)
+    result << [elem, target] if arr.include?(target)
+  end
+  result
+end
+
+alias :f :array_pair_sum
+
+puts f(10, [3, 4, 5, 6, 7]).to_s # => [[3, 7], [4, 6]]
+puts f(8, [3, 4, 5, 4, 4]).to_s  # => [[3, 5], [4, 4]]
\ No newline at end of file
diff --git a/solutions/ruby/balanced_brackets.rb b/solutions/ruby/balanced_brackets.rb
index f961db1..e9bb45d 100644
--- a/solutions/ruby/balanced_brackets.rb
+++ b/solutions/ruby/balanced_brackets.rb
@@ -6,5 +6,5 @@ def balanced_brackets(str)
     if brackets[c] then arr << c 
     else return false if arr.size < 1 || (brackets.key(c) != arr.pop) end
   end
-  arr.size == 0 ? true : false
+  arr.empty?
 end