20

ruby/20-Valid-Parentheses.rb

@@ -0,0 +1,17 @@
+def is_valid(s)
+  paren = []
+  match = {
+    '{' => '}',
+    '(' => ')',
+    '[' => ']'
+  }
+  s.each_char do |char|
+    if match.key?(char)
+      paren << char
+    else
+      return false if paren.empty?
+      return false if match[paren.pop] != char
+    end
+  end
+  paren.empty?
+end