﻿ leetcode笔记：Integer to English Words-C 语言_软件编程-脚本宝典

# leetcode笔记：Integer to English Words

## leetcode笔记：Integer to English Words

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"``````

Hint:

Did you see a pattern in dividing the number into chunk of words? For example, 123 and 123000. Group the number by thousands (3 digits). You can write a helper function that takes a number less than 1000 and convert just that chunk to words. There are many edge cases. What are some good test cases? Does your code work with input such as 0? Or 1000010? (middle chunk is zero and should not be printed out)

``````class Solution
{
public:
string numberToWords(int num) {
//  num的最大值：2,147,483,647
const string unit[4] = {"", " Thousand", " Million", " Billion"};
string result;
int partNum[4];
for (int i = 0; i < 4; ++i)
{
partNum[i] = num % 1000;
num /= 1000;
if (partNum[i] == 0) continue;
result = stitch(partNum[i]) + unit[i] + result;
}
// 去掉result首位的空格
return result.size() ? result.substr(1) : "Zero";
}

private:
string stitch(int num) {
const string lessTen[10] =
{"", " One", " Two", " Three", " Four", " Five", " Six", " Seven", " Eight", " Nine"};
const string lessTwenty[10] =
{" Ten", " Eleven", " Twelve", " Thirteen", " Fourteen", " Fifteen", " Sixteen",
" Seventeen", " Eighteen", " Nineteen"};
const string lessHundred[10] =
{"", "", " Twenty", " Thirty", " Forty", " Fifty", " Sixty", " Seventy",
" Eighty", " Ninety"};

string temp;

if (num != 0)
{
int units, tens, hundreds; // 个位、十位、百位出现的
hundreds = num / 100;
tens = (num % 100) / 10;
units = (num % 100) % 10;

if (hundreds != 0)
temp = temp + lessTen[hundreds] + " Hundred";

if (tens != 0)
{
if (tens == 1)
{
temp += lessTwenty[units];
return temp;
}
else
temp += lessHundred[tens];
}

if (units != 0)
temp += lessTen[units];
}
return temp;
}
};``````

Tags：

﻿
<