Google Code Jam Qualification Rounds Problem #3

candy_splitting.rb

#!/usr/bin/env ruby

data = []
file_data = File.read(ARGV[0]).split("\n")
is_case_line = false
1.upto(file_data.length - 1) do |i|
  data << file_data[i].split(" ").map { |n| n.to_i } if is_case_line
  is_case_line = (is_case_line) ? false : true
end

def decimal_to_binary(number) 
  number.to_s(2)
end

def sum(a, b) 
  total = eval("0b#{a.to_s(2)}^0b#{b.to_s(2)}")
end

def rest(full_arr, sub_arr) 
  temp = full_arr.dup
  sub_arr.each { |val| temp.slice! temp.index(val) }
  temp
end

output_file = File.open("output.txt", "w")
data.each_with_index do |arr, case_number|
  largest = 0
  a_index = 1
  b_index = arr.length - 1
  until a_index > b_index
    left_sides = arr.combination(a_index).to_a
    left_sides.each do |side|
      right_side = rest(arr, side)

      seans_total         = side.inject { |current_sum, n| sum(current_sum, n) }
      patricks_total      = right_side.inject { |current_sum, n| sum(current_sum, n) }
      seans_real_total    = side.inject { |current_sum, n| current_sum + n }
      patricks_real_total = right_side.inject { |current_sum, n| current_sum + n }

      if seans_total == patricks_total
        if seans_total > patricks_total
          largest = seans_real_total if seans_real_total > largest
        else
          largest = patricks_real_total if patricks_real_total > largest
        end
      end

    end

    a_index += 1
    b_index -= 1
  end

  value  = (largest == 0) ? "NO" : largest
  ending = (case_number + 1 == data.length) ? "" : "\n" 
  output_file.print "Case ##{case_number + 1}: #{value}#{ending}"
end