0273

0201-0300/0273_integer_to_english_words.rb

@@ -0,0 +1,79 @@
+# @param {Integer} num
+# @return {String}
+def number_to_words(num)
+ return 'Zero' if num.zero?
+
+ map_3_digits = {
+ 0 => nil,
+ 1 => 'One',
+ 2 => 'Two',
+ 3 => 'Three',
+ 4 => 'Four',
+ 5 => 'Five',
+ 6 => 'Six',
+ 7 => 'Seven',
+ 8 => 'Eight',
+ 9 => 'Nine',
+ 10 => 'Ten',
+ 11 => 'Eleven',
+ 12 => 'Twelve',
+ 13 => 'Thirteen',
+ 14 => 'Fourteen',
+ 15 => 'Fifteen',
+ 16 => 'Sixteen',
+ 17 => 'Seventeen',
+ 18 => 'Eighteen',
+ 19 => 'Nineteen',
+ 20 => 'Twenty',
+ 30 => 'Thirty',
+ 40 => 'Forty',
+ 50 => 'Fifty',
+ 60 => 'Sixty',
+ 70 => 'Seventy',
+ 80 => 'Eighty',
+ 90 => 'Ninety',
+ 100 => 'One Hundred',
+ 200 => 'Two Hundred',
+ 300 => 'Three Hundred',
+ 400 => 'Four Hundred',
+ 500 => 'Five Hundred',
+ 600 => 'Six Hundred',
+ 700 => 'Seven Hundred',
+ 800 => 'Eight Hundred',
+ 900 => 'Nine Hundred',
+ }
+
+ convert_3_digits = lambda { |n|
+ return map_3_digits[n] if map_3_digits.has_key?(n)
+
+ str = []
+ power = 100
+ while n > 0
+ if map_3_digits.has_key?(n)
+ str << map_3_digits[n]
+ break
+ end
+
+ r = n % power
+ str << map_3_digits[n - r] if map_3_digits[n - r]
+ n = r
+ power /= 10
+ end
+
+ str.join(' ')
+ }
+
+ chunks_map = [nil, 'Thousand', 'Million', 'Billion', 'Trillion']
+
+ str = []
+ chunks_map.each { |name|
+ if convert = convert_3_digits.call(num % 1000)
+ convert += ' ' + name if name
+ str.unshift(convert)
+ end
+ num /= 1000
+ break if num <= 0
+ }
+
+ str.join(' ')
+end