Generate Phone Letter Combinations | Dataford Interview Questions

Generate all possible strings from a string of phone number digits using a digit-to-letters mapping.

Use the standard mapping 2 -> abc, 3 -> def, ..., 9 -> wxyz. Implement letter_combinations(digits), which accepts a non-empty string containing digits from 2 through 9 and returns a list of every possible combination. Return combinations in lexicographic order based on the mapping order.

Example: digits = "23" returns ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"]. Example: digits = "7" returns ["p", "q", "r", "s"].

Constraints: 1 <= len(digits) <= 10; each character is a digit from 2 through 9.

Constraints

1 <= len(digits) <= 10
Each character in digits is one of '2' through '9'
Return all combinations in lexicographic order based on the mapping order

Function Signature

def letter_combinations(digits):

Your question is Generate Phone Letter Combinations. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem