FastPrep
Problem · String

Phone Keypad Letter Combinations

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Problem statement

Given a string digits, return every letter combination that the digits could represent on a conventional telephone keypad.

The problem statement continues
Pro

Examples

Example 1

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

Choose one of abc for the first position and one of def for the second, following left-to-right depth-first order.

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FastPrep Pro
Reported in 1 Google interview this week

Unlock this recently reported problem

FastPrep Pro gives you full access to interview problems reported within the last week.

  • Full problem statement and constraints
  • 1 more worked example, explained
  • Guided hints and editorial
  • Run your code on real test cases
$9/month

Pro subscription, billed yearly — or $19 month-to-month. Cancel anytime.

Free plan — 2 of 2 free unlocks used this week