Spell a Nonnegative Signed Integer in English Words
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: hard
Interview Round: Other
### Problem
Convert num into ordinary English number words using the format illustrated here: capitalized number words separated by single spaces, with Thousand, Million and Billion scales and no "and" or hyphens. Zero is "Zero".
```cpp
string numberToWords(int num);
```
### Examples
```text
num = 1010 -> "One Thousand Ten"
num = 1000001 -> "One Million One"
```
### Constraints
- 0 <= num <= 2147483647.
Overview: Spell a Nonnegative Signed Integer in English Words. Convert num into ordinary English number words using the format illustrated here: capitalized number words separated by single spaces, with Thousand, Million an
