Convert digit/number to words
Detailed guide and Python implementation for the 'Convert digit/number to words' problem.
Problem Statement
Write a function number_to_words(n) that takes a non-negative integer n and returns a string where each digit is converted to its English word, separated by spaces.
Digit-word mapping: 0='Zero', 1='One', 2='Two', 3='Three', 4='Four', 5='Five', 6='Six', 7='Seven', 8='Eight', 9='Nine'.
For example, 123 → 'One Two Three'.
- •0 <= n <= 10^9
Examples
number_to_words(123)
'One Two Three'
1 → 'One', 2 → 'Two', 3 → 'Three'. Joined with spaces.
number_to_words(405)
'Four Zero Five'
4 → 'Four', 0 → 'Zero', 5 → 'Five'.
number_to_words(0)
'Zero'
Single digit 0 → 'Zero'.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
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