Problem · String

Rearrange Digits Under an Adjacent-Sum Limit

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Problem statement

You are given a non-empty string digits containing decimal digits. Rearrange every character exactly once so that the numeric values of every two adjacent digits have sum at most 9.

The problem statement continues
Pro

Examples

Example 1

digits = "188"return = "818"

The only valid arrangement places 1 between the two 8s. Its adjacent sums are both 9.

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FastPrep Pro
Reported in 1 Amazon 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
  • 2 more worked examples, 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