[hard]273. Integer to English Words

<span style="font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; background-color: rgb(255, 255, 255);">273. Integer to English Words</span>

Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1.

For example,

123 -> "One Hundred Twenty Three"12345 -> "Twelve Thousand Three Hundred Forty Five"1234567 -> "One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven"

Solution:

It's a super easy problem. Just make sure you have every detail checked.

(Forgot to install a Chinese language input, sorry

Here is my code.

class Solution {public:    string num[9] = {"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};    string teens[10] = {"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};    string tens[8] = {"Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};    string units[4] = {"", "Thousand", "Million", "Billion"};    string under_1000(int x) {        string ans;        int hun = x / 100;        int ten = (x % 100) / 10;        int sig = x % 10;        bool first = true;            if (hun) {            ans += num[hun - 1] + " Hundred";            first = false;        }        if (ten) {            if (ten >= 2) {                if (!first)                    ans += ' ';                ans += tens[ten - 2];                if (sig)                    ans += ' ' + num[sig - 1];                first = false;            } else {                if (!first)                    ans += ' ';                ans += teens[sig];            }        } else {            if (sig) {                if (!first)                    ans += ' ';                ans += num[sig - 1];            }        }        return ans;    }    string numberToWords(int num) {        string ans; int count = 0;        if (!num)            return "Zero";        while (num) {            if (num % 1000 != 0) {                string str = under_1000(num % 1000);                if (str != "")                    if (ans != "")                        ans = str + ' ' + units[count] + ' ' + ans;                    else                        if (units[count] != "")                            ans = str + ' ' + units[count];                        else ans = str;            }            num /= 1000;            ++ count;        }        return ans;    }};