Phone Number Combinations

Given a string digits containing 2 to 9 inclusive, return in sorted lexicographic order all possible strings it could represent when mapping to letters on a phone dialpad.

These are the mappings on a phone dialpad:

| 2 | abc  |
| 3 | def  |
| 4 | ghi  |
| 5 | jkl  |
| 6 | mno  |
| 7 | pqrs |
| 8 | tuv  |
| 9 | wxyz |

https://binarysearch.com/problems/Phone-Number-Combinations

Examples

Example 1

Input

• digits = 23

Output

• answer = ['ad', 'ae', 'af', 'bd', 'be', 'bf', 'cd', 'ce', 'cf']

Solution

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