戶籍代表的字母數字：
Ａ台北市-10 Ｂ台中市-11 Ｃ基隆市-12 Ｄ台南市-13 Ｅ高雄市-14 Ｆ台北縣-15
Ｇ宜蘭縣-16 Ｈ桃園縣-17 Ｉ嘉義市-34 Ｊ新竹縣-18 Ｋ苗栗縣-19 Ｌ台中縣-20
Ｍ南投縣-21 Ｎ彰化縣-22 Ｏ新竹市-35 Ｐ雲林縣-23 Ｑ嘉義縣-24 Ｒ台南縣-25
Ｓ高雄縣-26 Ｔ屏東縣-27 Ｕ花蓮縣-28 Ｖ台東縣-29 Ｗ金門縣-32 Ｘ澎湖縣-30
Ｙ陽明山-31 Ｚ連江縣-33

公式
A123456789 -> 10123456789

1   0   1    2    3    4    5    6    7   8   9 (拆解字母後的數字)
*   *   *    *    *    *    *    *    *   *   *
1   9   8    7    6    5    4    3    2   1   1 (固定係數)
-----------------------------------------------
1 + 0 + 8 + 14 + 18 + 20 + 20 + 18 + 14 + 8 + 9 = 130

130 % 10 == 0

require 'benchmark'

LOCATION_CODE = {
  'A' => [1, 0], 'B' => [1, 1], 'C' => [1, 2], 'D' => [1, 3], 'E' => [1, 4], 'F' => [1, 5], 'G' => [1, 6], 'H' => [1, 7], 'I' => [3, 4],
  'J' => [1, 8], 'K' => [1, 9], 'L' => [2, 0], 'M' => [2, 1], 'N' => [2, 2], 'O' => [3, 5], 'P' => [2, 3], 'Q' => [2, 4], 'R' => [2, 5],
  'S' => [2, 6], 'T' => [2, 7], 'U' => [2, 8], 'V' => [2, 9], 'W' => [3, 2], 'X' => [3, 0], 'Y' => [3, 1], 'Z' => [3, 3]
}

MULTIPLIER = [1, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1]

def id_card_validate(id)
  return false unless id =~ /\A[A-Z](1|2)\d{8}\z/
  chars = id.chars
  numbers = LOCATION_CODE[chars.shift] + chars.map(&:to_i)
  sum = numbers.zip(MULTIPLIER).map{ |a, b| a * b }.reduce(:+)
  # sum, i = 0, 0
  # while i <= 10
  #   sum += numbers[i] * MULTIPLIER[i]
  #   i += 1
  # end
  (sum % 10).zero?
end

n = 100000
Benchmark.bmbm do |x|
  x.report('leonji'){ n.times{ id_card_validate('A123456789') } }
end

# Rehearsal ------------------------------------------
# leonji   0.770000   0.010000   0.780000 (  0.796012)
# --------------------------------- total: 0.780000sec

#              user     system      total        real
# leonji   0.770000   0.000000   0.770000 (  0.792737)