LeetCode - Integer to English Words

最新推荐文章于 2020-06-08 06:56:35 发布

原创最新推荐文章于 2020-06-08 06:56:35 发布 · 180 阅读

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本文介绍了一种将整数转换为英文表示的方法，通过使用预定义的字符串向量，该算法能够正确处理从零到数十亿之间的整数，并考虑了英语中特定的规则，如百位数的表达和千、百万、十亿的单位。

class Solution {
public:
    string numberToWords(int num) {
        vector<string> three{"Thousand", "Million", "Billion"};
        string res =hundred(num%1000);
        int three_idx = 0;
        while(num>0){
            num /= 1000;
            res = num%1000? hundred(num%1000)+" "+three[three_idx]+(res.empty()?"":" "+res):res;       
            three_idx++;
        }
        return res.empty()?"Zero":res;
    }
    string hundred(int num){
        vector<string> v1 = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};
        vector<string> v2 = {"", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};
        string res="";
        if(num/100!=0) res+=v1[num/100]+" Hundred";
        if(num%100<20){
            return res+=(!res.empty()&&num%100!=0?" ":"")+v1[num%100];
        }
        return res+=(res.empty()?"":" ")+v2[num%100/10]+(num%10==0?"":" "+v1[num%10]);
    }
};

感觉这道题的难点其实在于如何处理中间的space