Integer to English Words
Created: November 11, 2018 by [lek-tin]
Last updated: October 2, 2019
Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1.
Example 1
Input: 123
Output: "One Hundred Twenty Three"
Example 2
Input: 12345
Output: "Twelve Thousand Three Hundred Forty Five"
Example 3
Input: 1234567
Output: "One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven"
Example 4
Input: 1234567891
Output: "One Billion Two Hundred Thirty Four Million Five Hundred Sixty Seven
Thousand Eight Hundred Ninety One"
Solution
class Solution:
def __init__(self):
self.lessThan20 = ["", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"]
self.tens = ["", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"]
self.thousands = ["", "Thousand", "Million", "Billion", "Trillion]
def numberToWords(self, num):
"""
:type num: int
:rtype: str
"""
if num == 0:
return "Zero";
i = 0;
words = ""
while num > 0:
n = num % 1000
if n != 0:
words = self.helper(n) + self.thousands[i] + " " + words
num //= 1000
i += 1
return words.strip()
def helper(self, num):
if num == 0:
return ""
elif num < 20:
return self.lessThan20[int(num)] + " "
elif num < 100:
# Any number under 100 can be decomposed to tens + a single digit
return self.tens[num // 10] + " " + self.helper(num % 10)
else:
return self.lessThan20[num // 100] + " Hundred " + self.helper(num % 100)
Iterative
class Solution:
def numberToWords(self, num: int) -> str:
if num == 0:
return "Zero"
underTwenty = {
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"
}
tens = {
20: "Twenty",
30: "Thirty",
40: "Forty",
50: "Fifty",
60: "Sixty",
70: "Seventy",
80: "Eighty",
90: "Ninety",
}
thousands = {
1: "",
1000: "Thousand",
1000000: "Million",
1000000000: "Billion"
}
words = []
for denome in [1000000000, 1000000, 1000, 1]:
temp = num//denome
num %= denome
if temp > 0:
hundreds = temp // 100
if hundreds > 0:
words.append(underTwenty[hundreds])
words.append("Hundred")
temp %= 100
if temp >= 20:
digit = temp % 10
words.append(tens[temp-digit])
if digit > 0:
words.append(underTwenty[digit])
elif temp > 0:
words.append(underTwenty[temp])
words.append(thousands[denome])
return " ".join(words).strip()