動機

天啊

Problem

Convert a non-negative integer num to its English words representation.

 

Example 1:

Input: num = 123Output: One Hundred Twenty Three

Example 2:

Input: num = 12345Output: Twelve Thousand Three Hundred Forty Five

Example 3:

Input: num = 1234567Output: One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven

Example 4:

Input: num = 1234567891Output: One Billion Two Hundred Thirty Four Million Five Hundred Sixty Seven Thousand Eight Hundred Ninety One

 

Constraints:

  • 0 <= num <= 231 - 1

Sol

先把3位數的function先做出來，之後就是慢慢往上推

class Solution:
    def numberToWords(self, num: int) -> str:
        v1 = ["", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"]
        v2 = ["", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"]
        v3 = ["Thousand", "Million", "Billion"]
        ret = []
        
        def hund(n):
            a,b,c = n//100, n%100, n%10
            if b < 20:
                ret = v1[b]
            elif c > 0:
                ret = f'{v2[b//10]} {v1[c]}'
            else:
                ret = f'{v2[b//10]}'
            if a > 0:
                if b > 0:
                    ret = f'{v1[a]} Hundred {ret}'
                else:
                    ret = f'{v1[a]} Hundred'
            return ret
        
        ret = hund(num%1000)
        for i in range(3):
            num = num//1000
            if num % 1000 > 0:
                ret = f'{hund(num%1000)} {v3[i]} {ret}'
        if ret:
            if ret[-1] == " ":
                return ret[:-1]
            else:
                return ret
        else:
            return "Zero"