exercism-71 Protein translation

Author: kumar91gopi

README.md

@@ -292,6 +292,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt
 68. [Run Length Encoding](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/run_length_encoding.rb)
 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)
 
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exercism/protein_translation.rb

@@ -0,0 +1,32 @@
+# Problem: https://exercism.org/tracks/ruby/exercises/protein-translation
+
+# Solution
+class InvalidCodonError < StandardError; end
+class Translation
+  CODON_PROTEIN_MAP = {
+    "AUG" => "Methionine",
+    "UUU" => "Phenylalanine",
+    "UUC" => "Phenylalanine",
+    "UUA" => "Leucine",
+    "UUG" => "Leucine",
+    "UCU" => "Serine", 
+    "UCC" => "Serine",
+    "UCA" => "Serine",
+    "UCG" => "Serine",
+    "UAU" => "Tyrosine",
+    "UAC" => "Tyrosine",
+    "UGU" => "Cysteine",
+    "UGC" => "Cysteine",
+    "UGG" => "Tryptophan"
+  }
+  STOP_CODONS = ["UAA", "UAG", "UGA"]
+  
+  def self.of_rna(strand)
+    return [] if strand.empty?
+    raise InvalidCodonError if strand.length < 3
+    codon = strand[0, 3]
+    return [] if STOP_CODONS.include?(codon)
+    raise InvalidCodonError if CODON_PROTEIN_MAP[codon].nil?
+    [CODON_PROTEIN_MAP[codon]] + of_rna(strand[3..-1])
+  end
+end