标签：string etc color english case 现在 rest and number
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"
最难的是要想到将一位数/二位数/三位数的方法单独列出，然后再判断是否加上billlion之类的。
很多细节需要考虑。
class Solution { public String one(int num) { switch(num) { case 1: return "One"; case 2: return "Two"; case 3: return "Three"; case 4: return "Four"; case 5: return "Five"; case 6: return "Six"; case 7: return "Seven"; case 8: return "Eight"; case 9: return "Nine"; } return ""; } public String twoSmallerThan20(int num){ switch(num) { case 10: return "Ten"; case 11: return "Eleven"; case 12: return "Twelve"; case 13: return "Thirteen"; case 14: return "Fourteen"; case 15: return "Fifteen"; case 16: return "Sixteen"; case 17: return "Seventeen"; case 18: return "Eighteen"; case 19: return "Nineteen"; } return ""; } public String ten(int num) { switch(num) { case 2: return "Twenty"; case 3: return "Thirty"; case 4: return "Forty"; case 5: return "Fifty"; case 6: return "Sixty"; case 7: return "Seventy"; case 8: return "Eighty"; case 9: return "Ninety"; } return ""; } public String two(int num) { if(num == 0) return ""; if(num < 10) { return one(num); }else if(num < 20) { return twoSmallerThan20(num); }else { int tenner = num/10; int rest = num - 10*tenner; if(rest != 0) { return ten(tenner) + " " + one(rest); }else{ return ten(tenner); } } } public String three(int num) { //其实前面的几个方法都是为这个方法服务的。只有three（）会出现在最后的主函数里。 int hundred = num/100; int rest = num - 100*hundred; if(hundred*rest != 0) { return one(hundred) + " Hundred " + two(rest); }else if(hundred == 0){ return two(rest); }else{ return one(hundred) + " Hundred"; //单独列出这个是因为这里的Hundred后面没有空格。 } } public String numberToWords(int num) { if(num == 0) return "Zero"; int billion = num/1000000000; int million = (num-billion*1000000000)/1000000; int thousand = (num-billion*1000000000-million*1000000)/1000; int rest = num - billion*1000000000-million*1000000 - thousand*1000; String result = ""; if(billion != 0){ result += three(billion) + " Billion"; } if(million != 0){ if(result != "") result += " "; //这里一定要判断一下要不要加空格 result += three(million) + " Million"; } if(thousand != 0){ if(result != "") result += " "; result += three(thousand) + " Thousand"; } if(rest != 0){ if(result != "") result += " "; result += three(rest); } return result; } }
leetcode 273. Integer to English Words
标签：string etc color english case 现在 rest and number
原文地址：https://www.cnblogs.com/jamieliu/p/10336174.html
