exercism-72 Wordy

Author: kumar91gopi

README.md

@@ -293,6 +293,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt
 69. [Robot Simulator](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/robot_simulator.rb)
 70. [Beer Song](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/beer_song.rb)
 71. [Protein Translation](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/protein_translation.rb)
+72. [Wordy](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/wordy.rb)
 
 <a name="leetcode"/>
 

exercism/wordy.rb

@@ -0,0 +1,72 @@
+# Problem: https://exercism.org/tracks/ruby/exercises/wordy
+
+# Solution
+class WordProblem
+    REPLACEMENTS = {
+                      "plus" => "+",
+                      "minus" =>"-",
+                      "divided by" => "/",
+                      "multiplied by" => "*",
+                      "what is" =>""
+                    }
+    OPERATIONS = {
+                      "+" => lambda{|a,b| a+b},
+                      "-" =>lambda{|a,b| a-b },
+                      "/" => lambda{|a,b| a/b },
+                      "*" => lambda{|a,b| a*b }
+                    }
+    def initialize(word_prob)
+      word_prob = word_prob.strip.gsub(/\b(?:#{REPLACEMENTS.keys.join('|')})\b/i, REPLACEMENTS)
+      @word_prob = word_prob[-1]=="?" ? word_prob[0...-1] : word_prob
+    end
+
+    def answer
+      words = @word_prob.split(" ")
+      result = 0
+      i=0
+      prev_num = nil
+      prev_op = nil
+      while i<words.length
+        if words[i].match?(/^-?\d+$/)
+          unless prev_num.nil? and prev_op.nil?
+            result = prev_op.call(prev_num,words[i].to_i)
+            prev_op = nil
+            prev_num = result
+          else
+            prev_num = words[i].to_i
+          end
+        elsif OPERATIONS.keys.include?(words[i])
+          prev_op = OPERATIONS[words[i]]
+        else
+          raise ArgumentError
+        end
+        i+=1
+      end
+      result
+    end
+end
+
+# Solution
+class WordProblem
+    attr_reader :question
+    OPERATIONS = {
+      'plus'       => :+,
+      'minus'      => :-,
+      'divided'    => :/,
+      'multiplied' => :*
+    }
+    def initialize(question)
+      @question = question
+    end
+    
+    def answer
+      numbers = question.scan(/(-?\d+)/).flatten.map(&:to_i)
+      operations = question.scan(/(plus|minus|multiplied|divided)/).flatten.
+        map { |op| OPERATIONS[op] }
+      raise ArgumentError if numbers.empty? || operations.empty?
+      equation = operations.unshift(:+).zip(numbers).flatten.compact
+      equation.each_slice(2).inject(0) do |sum, (operation, number)|
+        sum.send(operation, number)
+      end
+    end
+end