rwz · January 3, 2014 20:49 · Jan 3, 2014
diff --git a/bm.rb b/bm.rb
@@ -0,0 +1,44 @@
+require "benchmark/ips"
+require "set"
+
+OLD_CODE = ->(n){
+  mod10 = n % 10
+  mod100 = n % 100
+
+  if mod10 == 1 && mod100 != 11
+    :one
+  elsif [2, 3, 4].include?(mod10) && ![12, 13, 14].include?(mod100)
+    :few
+  elsif mod10 == 0 || (5..9).to_a.include?(mod10) || (11..14).to_a.include?(mod100)
+    :many
+  else
+    :other
+  end
+}
+
+FROM_2_TO_4   = (2..4).to_set
+FROM_5_TO_9   = (5..9).to_set
+FROM_11_TO_14 = (11..14).to_set
+FROM_12_TO_14 = (12..14).to_set
+
+NEW_CODE = ->(n){
+  mod10 = n % 10
+  mod100 = n % 100
+
+  if mod10 == 1 && mod100 != 11
+    :one
+  elsif FROM_2_TO_4.include?(mod10) && !FROM_12_TO_14.include?(mod100)
+    :few
+  elsif mod10 == 0 || FROM_5_TO_9.include?(mod10) || FROM_11_TO_14.include?(mod100)
+    :many
+  else
+    :other
+  end
+}
+
+SAMPLE = 1000.times.map{ rand(0...999) } + 100.times.map{ rand(0...999).to_f / 10 }
+
+Benchmark.ips do |x|
+  x.report("old code"){ SAMPLE.each{ |n| OLD_CODE[n] }}
+  x.report("new code"){ SAMPLE.each{ |n| NEW_CODE[n] }}
+end