ajesler · June 16, 2022 03:40 · Jun 16, 2022 · Apr 8, 2020 · Apr 8, 2020
diff --git a/sock_market.rb b/sock_market.rb
@@ -12,23 +12,37 @@
 # Run solver specs with
 # $ ruby sock_merchant.rb --specs
 
+require "bundler/inline"
+
+# Uncomment this block to install byebug
+# gemfile true do
+#   source "https://rubygems.org"
+
+#   gem "test-unit"
+
+#   # Useful for debugging
+#   gem "byebug", platforms: [:mri, :mingw, :x64_mingw]
+#   gem "pry-byebug"
+# end
+
+require 'test/unit'
+Test::Unit::AutoRunner.need_auto_run = false
+
 class SockCounter
   def initialize(socks)
     @socks = socks
   end
 
   def pair_count
     # group by type
+    # binding.pry
     count_per_type = @socks.group_by(&:itself)
     pairs_per_type = count_per_type.transform_values { |v| v.size.div 2 }
     total_pairs = pairs_per_type.values.sum
     total_pairs
   end
 end
 
-require 'test/unit'
-Test::Unit::AutoRunner.need_auto_run = false
-
 class SockCounterSpec < Test::Unit::TestCase
   def expect_pair_count(expected_pair_count, socks:)
     pair_count = SockCounter.new(socks).pair_count

diff --git a/sock_market.rb b/sock_market.rb
@@ -55,9 +55,9 @@ def test_some_pairs
     # Run the specs
     Test::Unit::AutoRunner.need_auto_run = true
   else
-    source = first_argument.nil? ? DATA.read : File.read(first_argument)
+    data_source = first_argument.nil? ? DATA.read : File.read(first_argument)
     # Run the solver
-    raw_number_of_socks, raw_socks = source.split(/\r?\n/, 2)
+    raw_number_of_socks, raw_socks = data_source.split(/\r?\n/, 2)
 
     number_of_socks = raw_number_of_socks.to_i
     socks = raw_socks.split(' ').map(&:to_i)

diff --git a/sock_market.rb b/sock_market.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+# The Sock Merchant
+# from https://www.hackerrank.com/challenges/sock-merchant/problem
+#
+# Run the solver with the input after __END__
+# $ ruby sock_merchant.rb
+#
+# Run the solver using a file as input
+# $ ruby sock_merchant.rb test_input.txt
+#
+# Run solver specs with
+# $ ruby sock_merchant.rb --specs
+
+class SockCounter
+  def initialize(socks)
+    @socks = socks
+  end
+
+  def pair_count
+    # group by type
+    count_per_type = @socks.group_by(&:itself)
+    pairs_per_type = count_per_type.transform_values { |v| v.size.div 2 }
+    total_pairs = pairs_per_type.values.sum
+    total_pairs
+  end
+end
+
+require 'test/unit'
+Test::Unit::AutoRunner.need_auto_run = false
+
+class SockCounterSpec < Test::Unit::TestCase
+  def expect_pair_count(expected_pair_count, socks:)
+    pair_count = SockCounter.new(socks).pair_count
+    assert_equal expected_pair_count, pair_count
+  end
+
+  def test_none
+    expect_pair_count(0, socks: [])
+  end
+
+  def test_no_pairs
+    expect_pair_count(0, socks: [1, 2, 3, 4])
+  end
+
+  def test_some_pairs
+    expect_pair_count(2, socks: [1, 2, 3, 4, 1, 2])
+  end
+end
+
+if $PROGRAM_NAME == __FILE__
+  first_argument = ARGV.shift
+
+  if first_argument == '--specs'
+    # Run the specs
+    Test::Unit::AutoRunner.need_auto_run = true
+  else
+    source = first_argument.nil? ? DATA.read : File.read(first_argument)
+    # Run the solver
+    raw_number_of_socks, raw_socks = source.split(/\r?\n/, 2)
+
+    number_of_socks = raw_number_of_socks.to_i
+    socks = raw_socks.split(' ').map(&:to_i)
+
+    if number_of_socks != socks.size
+      raise("Sock mismatch! Expected #{number_of_socks}, got #{socks.size}")
+    end
+
+    pairs = SockCounter.new(socks).pair_count
+    puts pairs
+  end
+end
+
+__END__
+9
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