How should I practice Letter Combinations of a Phone Number?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Bloomberg LP phone screen problems in FastPrep.

Is Letter Combinations of a Phone Number associated with Bloomberg LP?

FastPrep tags this as a Bloomberg LP phone screen coding practice problem when the problem catalog has that company and stage context.

Letter Combinations of a Phone Number

Bloomberg LP● MediumNEW GRADPHONE SCREEN

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Problem statement

Digits 2 through 9 map to letters as on a telephone keypad. Return every string formed by choosing one mapped letter for each input digit.

Return an empty list for an empty input, and otherwise return combinations in lexicographic keypad order.

Function

letterCombinations(digits: String) → String[]

Examples

Example 1

digits = "23"return = ["ad","ae","af","bd","be","bf","cd","ce","cf"]

Choose one of abc for 2 and one of def for 3.

Constraints

0 <= digits.length <= 8
Every character is between 2 and 9.