LeetCode 273 Integer to English Words

递归实现billion million thousand hundred 的实现

可以通过num与1000000000, 1000000, 1000, 50, 1的比较来实现不同的invert

 1     string num1[20] = {"Zero","One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen"};
 2     string num2[10] =     {"Zero","Ten","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety"};
 3     string invert(int num){
 4         string str = "";
 5         if(num >= 1000000000){
 6             return invert(num/1000000000)+" Billion" + invert(num%1000000000);
 7         }else if(num >= 1000000){
 8             return invert(num/1000000)+ " Million" + invert(num%1000000);
 9         }else if(num >= 1000){
10             return invert(num/1000) + " Thousand" + invert(num%1000);
11         }else if(num >= 100){
12             return invert(num/100) + " Hundred" + invert(num%100);
13         }else if(num >= 20){
14             return " " + num2[num/10] + invert(num%10);
15         }else if(num >=1){
16             return " " + num1[num];
17         }else{
18             return "";
19         }
20     }
21     //程序入口
22     string numberToWords(int num) {
23         if(num==0) return num1[num];
24         else{
25             string result = invert(num);
26             result.erase(result.begin());
27             return result;
28         }
29     }

 

posted @ 2015-12-04 15:54  Acker  阅读(131)  评论(0)  编辑  收藏  举报